codehs.com

codehs.com is SSL secured

Free website and domain report on codehs.com

Last Updated: 23rd July, 2021 Update Now
Overview

Snoop Summary for codehs.com

This is a free and comprehensive report about codehs.com. Codehs.com is hosted in United States on a server with an IP address of 13.226.36.123, where the local currency is USD and English is the local language. Codehs.com is expected to earn an estimated $93 USD per day from advertising revenue. The sale of codehs.com would possibly be worth $67,880 USD. This figure is based on the daily revenue potential of the website over a 24 month period. Codehs.com is wildly popular with an estimated 21,985 daily unique visitors. This report was last updated 23rd July, 2021.

About codehs.com

Site Preview: codehs.com codehs.com
Title: CodeHS - Teach Coding and Computer Science at Your School | CodeHS
Description:
Keywords and Tags: popular, technical information
Related Terms:
Fav Icon:
Age: Over 12 years old
Domain Created: 26th March, 2012
Domain Updated: 13th December, 2016
Domain Expires: 26th March, 2027
Review

Snoop Score

3/5 (Great!)

Valuation

$67,880 USD
Note: All valuation figures are estimates.

Popularity

High
Note: Popularity is estimated.

Rank, Reach and Authority

Alexa Rank: 34,148
Alexa Reach:
SEMrush Rank (US):
SEMrush Authority Score:
Moz Domain Authority: 0
Moz Page Authority: 0

Organic vs Paid (Google Ads)

Traffic

Visitors

Daily Visitors: 21,985
Monthly Visitors: 669,154
Yearly Visitors: 8,024,525
Note: All visitors figures are estimates.

Visitors By Country

Revenue

Revenue

Daily Revenue: $93 USD
Monthly Revenue: $2,830 USD
Yearly Revenue: $33,935 USD
Note: All revenue figures are estimates.

Revenue By Country

SEO

Backlinks Analysis (SEMrush)

Top New Follow Links

Top Ranking Keywords (US)

Domain Analysis

Value Length
Domain: codehs.com 10
Domain Name: codehs 6
Extension (TLD): com 3
Expiry Check:

Page Speed Analysis

Average Load Time: 3.10 seconds
Load Time Comparison: Faster than 21% of sites

PageSpeed Insights

Avg. (All Categories) 61
Performance 40
Accessibility 88
Best Practices 67
SEO 64
Progressive Web App 45
0–49 (Fail) 50–89 (Average) 90–100 (Pass)
URL: https://codehs.com/
Updated: 23rd July, 2021

2.24 seconds
First Contentful Paint (FCP)
65%
19%
16%

0.01 seconds
First Input Delay (FID)
94%
3%
3%

Simulate loading on desktop
40

Performance

Indicates how well the page is performing and highlights opportunities where performance may be improved for codehs.com. This includes details about optimizing page load times which can result in a better user experience.

Opportunities

Minify CSS
Cascading Style Sheets (CSS) files can contribute to network payload sizes. Codehs.com should consider minifying CSS files.
Minify JavaScript
JavaScript (JS) files can contribute to network payload sizes and increase script parse times. Codehs.com should consider minifying JS files.
Efficiently encode images — Potential savings of 25 KiB
Unoptimized images can consume more cellular data than what is necessary.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
25842
Enable text compression
Text-based resources should be served with compression, such as gzip, deflate or brotli.
Preconnect to required origins
Resource hints, such as 'preconnect' or 'dns-prefetch', may assist in establishing early connections to important third-party origins.
Initial server response time was short — Root document took 90 ms
It is advised to keep the server response time short for the main document, because all other requests depend on it.
URL Time Spent (Ms)
https://codehs.com/
86.373
Avoid multiple page redirects — Potential savings of 190 ms
Redirects can cause additional delays before the page can begin loading. Codehs.com should avoid multiple or unnecessary page redirects.
URL Time Spent (Ms)
http://codehs.com/
190
https://codehs.com/
0
Use video formats for animated content
Large GIFs are inefficient for delivering animated content. It is recommended to use MPEG4/WebM videos for animations and PNG/WebP for static images instead of GIF.
Remove duplicate modules in JavaScript bundles
Ensure that no duplicate JavaScript modules from bundles exist to reduce bytes consumed by network activity.
Avoid serving legacy JavaScript to modern browsers — Potential savings of 20 KiB
Polyfills and transforms enable legacy browsers to use new JavaScript features. For bundled JavaScript it is recommended to adopt a modern script deployment strategy using module/nomodule feature detection. This will reduce the amount of code shipped to modern browsers.
URL Potential Savings (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
10184
https://unpkg.com/tableexport.jquery.plugin@1.10.26/libs/jsPDF/jspdf.min.js
10068
https://js.intercomcdn.com/vendor-modern.0c2722c5.js
104
https://unpkg.com/tableexport.jquery.plugin@1.10.26/libs/jsPDF-AutoTable/jspdf.plugin.autotable.js
56

Diagnostics

Avoid chaining critical requests — 12 chains found
Below is a list of Critical Request Chains, which shows which resources are loaded with a high priority. Codehs.com should consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
User Timing marks and measures — 4 user timings
Make use of the User Timing API to measure an app's real-world performance during key user experiences.
Name Type Start Time (Ms) Duration (Ms)
mark_pe
Mark
1378.159
mark_fs
Mark
1529.953
mark_qoes
Mark
1544.373
mark_ol
Mark
1971.401
JavaScript execution time — 0.9 s
JavaScript (JS) execution time can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
URL Total CPU Time (Ms) Script Evaluation (Ms) Script Parse (Ms)
https://codehs.com/
373.205
11.749
3.319
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
363.393
254.057
57.577
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
324.838
271.868
41.69
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
214.902
186.703
5.003
Unattributable
187.674
6.789
0.118
https://js.intercomcdn.com/frame-modern.7401e6d2.js
98.596
84.742
4.37
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
68.519
0
0
https://www.youtube.com/embed/VXKG_VtR3Yc?rel=0&showinfo=0
50.082
17.84
4.052
Minimizes main-thread work — 1.9 s
Main-thread work timing can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
Category Time Spent (Ms)
Script Evaluation
983.139
Other
398.997
Style & Layout
182.21
Script Parsing & Compilation
154.133
Parse HTML & CSS
113.894
Rendering
47.07
Garbage Collection
39.03
Keep request counts low and transfer sizes small — 97 requests • 5,733 KiB
It is advised to add a budgets.json file in order to set budgets for the quantity and size of page resources.
Resource Type Requests Transfer Size (Bytes)
Total
97
5870331
Image
37
3050338
Script
25
2017542
Stylesheet
8
359440
Font
11
318749
Document
2
87445
Other
13
30039
Media
1
6778
Third-party
52
2167722
Largest Contentful Paint element — 1 element found
The element which was identified as the Largest Contentful Paint.
Element
Avoid large layout shifts — 5 elements found
Below is a list of all DOM elements that contribute to the CLS of the page.
Element CLS Contribution
0.065796695693177
0.027373047514881
0.025345414365631
0.017741790055941
0.013737214586172
Avoids `document.write()`
Avoid or limit the use of external scripts that are dynamically injected via 'document.write()' as users on slow connections will be delayed by tens of seconds.
Avoid long main-thread tasks — 9 long tasks found
Below is a list of the longest tasks on the main thread, which is useful when identifying the worst input delay contributors.
URL Start Time (Ms) Duration (Ms)
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
3140
235
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
4210
160
https://codehs.com/
478
136
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
2861
120
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
2981
79
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
1970
69
https://js.intercomcdn.com/frame-modern.7401e6d2.js
4997
62
https://apis.google.com/js/api.js
6610
60
https://codehs.com/
423
55
Avoid non-composited animations
It is recommended to avoid non-composited animations which are often janky and increase CLS.

Budgets

Performance budget
It is advised to keep the quantity and size of all network requests under the targets set by the provided performance budget.
Timing budget
It is advised to set a timing budget to monitor the performance of your site.

Other

Network Requests
Below is a list of network requests that were made during page load.
URL Protocol Start Time (Ms) End Time (Ms) Transfer Size (Bytes) Resource Size (Bytes) Status Code MIME Type Resource Type
http://codehs.com/
http/1.1
0
47.768000047654
448
0
301
text/html
https://codehs.com/
h2
48.256000038236
133.6319996044
64991
206517
200
text/html
Document
https://kit.fontawesome.com/9f6f20dc9f.js
h2
148.16099964082
200.54399967194
4705
10865
200
text/javascript
Script
https://cdn.jsdelivr.net/gh/kenwheeler/slick@1.8.1/slick/slick.css
h2
148.31899991259
172.29199968278
1382
1776
200
text/css
Stylesheet
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.css
h2
148.50199967623
224.95900001377
27932
145689
200
text/css
Stylesheet
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
h2
148.70899962261
309.13800001144
261320
2034127
200
text/css
Stylesheet
https://use.typekit.net/xdy5aym.js
h2
226.73799982294
469.4039998576
7247
18072
200
text/javascript
Script
https://ajax.googleapis.com/ajax/libs/webfont/1.6.26/webfont.js
h2
316.67099986225
330.68999974057
6306
13188
200
text/javascript
Script
https://www.googletagmanager.com/gtag/js?id=AW-982588809
h2
392.31000002474
409.29699968547
38940
96379
200
application/javascript
Script
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
h2
392.50699989498
581.55799983069
175315
645074
200
application/javascript
Script
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
h2
392.84799993038
574.73400002345
902886
3370260
200
application/javascript
Script
https://apis.google.com/js/api.js
h2
392.99599966034
1127.2179996595
6332
12868
200
application/javascript
Script
https://unpkg.com/tableexport.jquery.plugin/tableExport.min.js
http/1.1
393.16199999303
533.79300003871
680
0
302
text/plain
https://unpkg.com/tableexport.jquery.plugin/libs/jsPDF/jspdf.min.js
http/1.1
393.2860000059
532.21999993548
685
0
302
text/plain
https://unpkg.com/tableexport.jquery.plugin/libs/jsPDF-AutoTable/jspdf.plugin.autotable.js
http/1.1
393.47200002521
532.68699999899
708
0
302
text/plain
https://static.codehs.com/img/brand_logo.png
h2
393.77299975604
457.49299973249
5915
5481
200
image/png
Image
https://static.codehs.com/img/logos/codehs_logo_white_text.png
h2
393.92399974167
415.63499998301
11223
10731
200
image/png
Image
https://static.codehs.com/img/program_icons/java-console.png
h2
394.10499995574
468.89099990949
5546
5055
200
image/png
Image
https://static.codehs.com/img/program_icons/graphics.png
h2
394.33999964967
456.95400005206
4253
3819
200
image/png
Image
https://static.codehs.com/img/program_icons/python.png
h2
394.51499981806
476.50099964812
6488
6054
200
image/png
Image
https://static.codehs.com/img/program_icons/html.png
h2
394.69099976122
474.88599969074
3625
3191
200
image/png
Image
https://static.codehs.com/img/program_icons/karel.png
h2
394.83199967071
471.51999967173
4236
3802
200
image/png
Image
https://uploads.codehs.com/b46469b780f8bb458a1728fc1c2e1497
h2
394.99499974772
475.22599995136
9987
9509
200
image/png
Image
https://static.codehs.com/img/homepage/editor.png
h2
395.18099976704
541.91899998114
444146
443653
200
image/png
Image
https://static.codehs.com/img/marketing/pro_page/activities.png
h2
395.36099974066
468.13899977133
29012
28520
200
image/png
Image
https://static.codehs.com/img/courses/intro_cs.png
h2
395.53799992427
470.66399967298
28056
27621
200
image/png
Image
https://static.codehs.com/img/courses/micro_bit.png
h2
395.73800005019
926.86799960211
174919
174426
200
image/png
Image
https://static.codehs.com/img/courses/intro_python.png
h2
395.89199982584
471.09899995849
23042
22550
200
image/png
Image
https://static.codehs.com/img/courses/cyber_security.png
h2
396.05199964717
474.32999964803
65094
64602
200
image/png
Image
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
h2
396.19599981233
485.78199977055
23820
23328
200
image/png
Image
https://static.codehs.com/img/homepage/badge_collage.png
h2
396.32199984044
483.94199972972
405896
405403
200
image/png
Image
https://static.codehs.com/img/homepage/pd.png
h2
396.43399976194
446.09500002116
212702
212209
200
image/png
Image
https://static.codehs.com/img/homepage/news/forbes_logo.png
h2
396.55700000003
462.78699999675
12156
11721
200
image/png
Image
https://static.codehs.com/img/homepage/news/usa_today_logo.png
h2
396.67799975723
794.1569997929
42556
42121
200
image/png
Image
https://static.codehs.com/img/homepage/news/edweek_logo.png
h2
396.84999966994
469.80999968946
36425
35990
200
image/png
Image
https://static.codehs.com/img/homepage/news/edsurge_logo.png
h2
397.06199988723
482.45899984613
23727
23294
200
image/png
Image
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
h2
397.42499962449
487.74999985471
37838
37404
200
image/jpeg
Image
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
h2
397.58899994195
481.94099962711
24754
24321
200
image/png
Image
https://static.codehs.com/img/homepage/news/today_logo.png
h2
397.76999969035
417.32099978253
5102
4668
200
image/png
Image
https://static.codehs.com/img/marketing/icons/chevron-left.png
h2
397.94399961829
431.1629999429
773
283
200
image/png
Image
https://static.codehs.com/img/homepage/articles/fashion_retail.png
h2
398.11599999666
467.21899975091
34678
34186
200
image/png
Image
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
h2
398.26799975708
516.8959996663
261427
260934
200
image/png
Image
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
h2
398.40599987656
486.5489997901
119294
118801
200
image/png
Image
https://static.codehs.com/img/logos/codehs_logo_dark_text.png
h2
398.57299998403
487.42999974638
11371
10879
200
image/png
Image
https://static.codehs.com/js/utils/include_by_ajax.js
h2
398.78299972042
894.82699986547
1501
998
200
application/javascript
Script
https://ka-f.fontawesome.com/releases/v5.15.3/css/free.min.css?token=9f6f20dc9f
h2
205.89399989694
233.95699961111
14083
60351
200
text/css
Fetch
https://ka-f.fontawesome.com/releases/v5.15.3/css/free-v4-shims.min.css?token=9f6f20dc9f
h2
206.16199960932
234.57299964502
5377
26701
200
text/css
Fetch
https://ka-f.fontawesome.com/releases/v5.15.3/css/free-v4-font-face.min.css?token=9f6f20dc9f
h2
206.64499979466
231.24199965969
1981
2956
200
text/css
Fetch
https://www.google-analytics.com/analytics.js
h2
398.91999959946
405.05399974063
20313
49377
200
text/javascript
Script
https://www.youtube.com/embed/VXKG_VtR3Yc?rel=0&showinfo=0
h2
408.86999992654
470.33299971372
22454
53107
200
text/html
Document
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
http/1.1
453.00999982283
1642.0950000174
841143
840728
200
image/png
Image
https://static.codehs.com/font/fontawesome-webfont.woff
h2
460.83300001919
510.09600004181
32525
31840
200
application/octet-stream
Font
https://ka-f.fontawesome.com/releases/v5.15.3/webfonts/free-fa-solid-900.woff2
h2
461.21099963784
519.85799986869
79417
78212
200
font/woff2
Font
https://ka-f.fontawesome.com/releases/v5.15.3/webfonts/free-fa-brands-400.woff2
h2
462.65199966729
502.62099970132
77935
76732
200
font/woff2
Font
https://unpkg.com/tableexport.jquery.plugin@1.10.26/libs/jsPDF/jspdf.min.js
h2
532.74999978021
583.25799973682
91580
307876
200
application/javascript
Script
https://unpkg.com/tableexport.jquery.plugin@1.10.26/libs/jsPDF-AutoTable/jspdf.plugin.autotable.js
h2
532.97599963844
556.86999997124
5050
15172
200
application/javascript
Script
https://unpkg.com/tableexport.jquery.plugin@1.10.26/tableExport.min.js
h2
534.04399985448
580.20700002089
15579
43335
200
application/javascript
Script
https://www.googleadservices.com/pagead/conversion_async.js
h2
784.72999995574
793.05400000885
14688
36573
200
text/javascript
Script
https://www.youtube.com/s/player/408a20d8/www-player-webp.css
h2
800.9529998526
826.03599969298
46436
331578
200
text/css
Stylesheet
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
h2
801.30099970847
808.5149996914
65996
197236
200
text/javascript
Script
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
h2
801.57299991697
831.79900003597
502685
1756926
200
text/javascript
Script
https://www.youtube.com/s/player/408a20d8/fetch-polyfill.vflset/fetch-polyfill.js
h2
801.80299980566
843.83299993351
3460
8543
200
text/javascript
Script
https://fonts.gstatic.com/s/roboto/v18/KFOmCnqEu92Fr1Mu4mxKKTU1Kg.woff2
h2
803.28799970448
806.66399979964
11506
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200
font/woff2
Font
https://googleads.g.doubleclick.net/pagead/viewthroughconversion/982588809/?random=1627043524944&cv=9&fst=1627043524944&num=1&bg=ffffff&guid=ON&resp=GooglemKTybQhCsO&u_h=600&u_w=800&u_ah=600&u_aw=800&u_cd=24&u_his=2&u_tz=-420&u_java=false&u_nplug=0&u_nmime=0&gtm=2oa7l1&sendb=1&ig=1&data=event%3Dgtag.config&frm=0&url=https%3A%2F%2Fcodehs.com%2F&tiba=CodeHS%20-%20Teach%20Coding%20and%20Computer%20Science%20at%20Your%20School%20%7C%20CodeHS&hn=www.googleadservices.com&async=1&rfmt=3&fmt=4
h2
869.63899992406
877.60399980471
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1674
200
text/javascript
Script
https://use.typekit.net/af/9b1c6c/00000000000000000001499c/21/l?subset_id=2&fvd=n7&v=3
h2
984.29099982604
1060.7479996979
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14768
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application/font-woff2
Font
https://use.typekit.net/af/4b77d9/0000000000000000000148a9/21/l?subset_id=2&fvd=i7&v=3
h2
984.68100000173
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application/font-woff2
Font
https://use.typekit.net/af/0e8ca9/0000000000000000000148a6/21/l?subset_id=2&fvd=n6&v=3
h2
984.92299998179
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17498
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application/font-woff2
Font
https://use.typekit.net/af/651407/0000000000000000000148a4/21/l?subset_id=2&fvd=n4&v=3
h2
985.1090000011
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17458
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application/font-woff2
Font
https://use.typekit.net/af/222d96/0000000000000000000148a5/21/l?subset_id=2&fvd=i4&v=3
h2
985.67099962384
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application/font-woff2
Font
https://use.typekit.net/af/04aaaa/0000000000000000000148a2/21/l?subset_id=2&fvd=n3&v=3
h2
985.81800004467
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17838
17520
200
application/font-woff2
Font
https://fonts.googleapis.com/css?family=Roboto
h2
988.2699996233
1007.4959998019
1288
2022
200
text/css
Stylesheet
https://static.codehs.com/img/karel/default/karel_east.png?time=1627043525239
h2
1200.7589996792
1254.8340000212
35163
34493
200
image/png
Image
https://static.codehs.com/img/karel/default/karel_north.png?time=1627043525239
h2
1201.0369999334
1303.8359996863
34447
33777
200
image/png
Image
https://static.codehs.com/img/karel/default/karel_west.png?time=1627043525239
h2
1201.3999996707
1222.3919997923
35411
34741
200
image/png
Image
https://static.codehs.com/img/karel/default/karel_south.png?time=1627043525239
h2
1201.6340000555
1273.991999682
34749
34079
200
image/png
Image
https://static.codehs.com/audio/bark3.mp3
h2
1254.6549998224
1319.1959997639
6778
6309
206
audio/mpeg
Media
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/deferred_compressed.css
h2
1255.5370000191
1545.4569999129
11484
57028
200
text/css
Stylesheet
https://static.codehs.com/lib/video-js/video-js.min.css
h2
1255.8059999719
1273.2259999029
3116
12117
200
text/css
Stylesheet
https://static.codehs.com/lib/jquery-ui/jquery-ui-1.8.18.custom.css
h2
1256.4009996131
1285.7289998792
6482
33011
200
text/css
Stylesheet
https://googleads.g.doubleclick.net/pagead/id
h2
1382.7410000376
1387.6429996453
1341
113
200
application/json
XHR
https://static.doubleclick.net/instream/ad_status.js
h2
1391.0069996491
1428.0829997733
653
29
200
text/javascript
Script
https://p.typekit.net/p.gif?s=1&k=xdy5aym&ht=tk&h=codehs.com&f=139.140.173.175.176.5474&a=1108077&js=1.20.0&app=typekit&e=js&_=1627043525480
h2
1401.4109997079
1423.5549997538
350
35
200
image/gif
Image
https://www.google-analytics.com/j/collect?v=1&_v=j91&a=1106279674&t=pageview&_s=1&dl=https%3A%2F%2Fcodehs.com%2F&dp=%2F&ul=en-us&de=UTF-8&dt=CodeHS%20-%20Teach%20Coding%20and%20Computer%20Science%20at%20Your%20School%20%7C%20CodeHS&sd=24-bit&sr=800x600&vp=1350x940&je=0&_u=aEBAAEABAAAAAC~&jid=1800533164&gjid=1552161038&cid=1959529930.1627043525&tid=UA-31691242-1&_gid=1220387925.1627043525&_r=1&_slc=1&z=617003299
h2
1459.6329997294
1463.1089996547
636
2
200
text/plain
XHR
https://www.google.com/pagead/1p-user-list/982588809/?random=1627043524944&cv=9&fst=1627041600000&num=1&bg=ffffff&guid=ON&u_h=600&u_w=800&u_ah=600&u_aw=800&u_cd=24&u_his=2&u_tz=-420&u_java=false&u_nplug=0&u_nmime=0&gtm=2oa7l1&sendb=1&data=event%3Dgtag.config&frm=0&url=https%3A%2F%2Fcodehs.com%2F&tiba=CodeHS%20-%20Teach%20Coding%20and%20Computer%20Science%20at%20Your%20School%20%7C%20CodeHS&async=1&fmt=3&is_vtc=1&random=1121038618&resp=GooglemKTybQhCsO&rmt_tld=0&ipr=y
h2
1465.7000000589
1484.4029997475
763
42
200
image/gif
Image
https://www.youtube.com/api/stats/qoe?event=streamingstats&cpn=pD-zzadsbxKzd4Hx&el=embedded&docid=VXKG_VtR3Yc&ns=yt&fexp=23748147%2C23858057%2C23983296%2C24001373%2C24002022%2C24002025%2C24004644%2C24007246%2C24045411%2C24053866%2C24058128%2C24058812%2C24060921%2C24068842&cl=386114545&seq=1&cbrand=apple&cbr=Chrome&cbrver=88.0.4324.175&c=WEB_EMBEDDED_PLAYER&cver=1.20210721.1.0&cplayer=UNIPLAYER&cos=Macintosh&cosver=10_14_6&cplatform=DESKTOP&vps=0.000:N,0.000:ER&cmt=0.000:0.000,0.000:0.000&error=0.000:html5.missingapi:0.000:nocodecs.1;a6s.0&vis=0.000:0&bh=0.000:0.000
1546.5679997578
1662.9719999619
0
0
-1
Ping
https://www.google.com/js/th/cBhk05BAbe_TcFEVIez2QMbpnXvZW_H7Pe80MJFxo1M.js
h2
1573.4830000438
1578.2979996875
15318
38371
200
text/javascript
Script
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/embed.js
h2
1626.4909999445
1630.6709996425
8190
25246
200
text/javascript
Script
https://fonts.gstatic.com/s/roboto/v27/KFOmCnqEu92Fr1Mu4mxKKTU1Kg.woff2
h2
1643.4949999675
1646.5519997291
11790
11032
200
font/woff2
Font
https://www.youtube.com/generate_204?VBlO5A
h2
1966.6299996898
1970.1689998619
251
0
204
text/plain
Image
https://widget.intercom.io/widget/x13jbr4h
http/1.1
1973.4119996428
1989.4609996118
409
0
302
https://js-agent.newrelic.com/nr-1210.min.js
h2
1974.8449996114
2000.5459999666
12427
31323
200
application/javascript
Script
https://js.intercomcdn.com/shim.latest.js
h2
1989.7069996223
2004.8960000277
6504
18297
200
application/javascript
Script
https://bam-cell.nr-data.net/1/5c532d628b?a=2416009&v=1210.e2a3f80&to=ZgRWZ0tRXBJXBhINVl9OckZXU0YIWQtJB1ZDBBpFUFVFEgwMCABcSQ%3D%3D&rst=2011&ck=1&ref=https://codehs.com/&qt=1&ap=110&be=391&fe=1975&dc=1444&perf=%7B%22timing%22:%7B%22of%22:1627043524078,%22n%22:0,%22f%22:49,%22dn%22:49,%22dne%22:49,%22c%22:49,%22ce%22:49,%22rq%22:49,%22rp%22:135,%22rpe%22:135,%22dl%22:140,%22di%22:531,%22ds%22:1444,%22de%22:1462,%22dc%22:1974,%22l%22:1974,%22le%22:1978%7D,%22navigation%22:%7B%7D%7D&fp=552&fcp=552&jsonp=NREUM.setToken
http/1.1
2012.1049997397
2155.126999598
877
49
200
text/javascript
Script
https://js.intercomcdn.com/frame-modern.7401e6d2.js
h2
2031.2419999391
2054.2909996584
69884
260239
200
application/javascript
Script
https://js.intercomcdn.com/vendor-modern.0c2722c5.js
h2
2031.5969996154
2049.230999779
39134
127366
200
application/javascript
Script
https://api-iam.intercom.io/messenger/web/ping
h2
2125.0599999912
2651.6239997
3179
9299
200
application/json
XHR
https://www.youtube.com/youtubei/v1/log_event?alt=json&key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8
h2
3740.0639997795
3756.1889998615
512
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200
application/json
XHR
Network Round Trip Times — 0 ms
High Network RTT (Round Trip Times) can have a large impact on performance. Providing servers geographically closer to the user could improve performance.
Server Backend Latencies — 0 ms
High server latencies indicate the server is overloaded or has a poor backend performance.
Tasks
Below is a list of the top-level main thread tasks that executed during page load.
Start Time (Ms) End Time (Ms)
142.546
7.364
158.952
5.617
207.458
6.576
231.893
6.325
242.286
6.697
321.661
68.519
390.89
26.682
417.585
109.604
530.435
5.685
547.272
8.37
564.97
7.657
573.997
18.894
595.893
5.889
602.124
7.069
610.046
20.662
630.743
136.043
767.579
8.035
780.153
17.74
810.156
36.745
865.708
10.291
878.739
7.5
887.19
320.513
1207.74
5.487
1213.935
10.359
1236.464
12.972
1249.701
10.214
1261.754
20.159
1282.171
119.551
1407.256
59.996
1477.317
157.279
1634.631
6.83
1641.587
5.496
1669.03
16.273
1687.89
5.468
1705.113
8.397
1719.085
11.063
1737.261
235.062
1976.909
6.637
2009.561
8.907
2019.294
16.086
2071.884
61.897
2657.909
25.316
3733.552
12.355
Diagnostics
Below is a collection of useful page vitals.
View Data
Metrics
Below is a collection of metrics.
View Data
Script Treemap Data
Provide as required, for treemap app.

Metrics

First Contentful Paint — 1.1 s
The time taken for the first image or text on the page to be rendered.
Speed Index — 2.3 s
The time taken for the page contents to be visibly populated.
Cumulative Layout Shift — 0.162
Cumulative Layout Shift is the measurement of visible elements collective movement within the viewport.
View Data

Other

Max Potential First Input Delay — 240 ms
Users could experience a delay when interacting with the page.
First Meaningful Paint — 1.1 s
The time taken for the primary content of the page to be rendered.

Opportunities

Eliminate render-blocking resources — Potential savings of 320 ms
Resources, such as JavaScript and style sheets, can block the first paint of the page. Codehs.com should consider delivering critical JavaScript/style sheets (JS/CSS) inline and deferring all non-critical JS/CSS.
URL Transfer Size (Bytes) Potential Savings (Ms)
https://cdn.jsdelivr.net/gh/kenwheeler/slick@1.8.1/slick/slick.css
1382
230
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.css
27932
310
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
261320
360
https://kit.fontawesome.com/9f6f20dc9f.js
4705
230
Reduce unused CSS — Potential savings of 347 KiB
Dead and/or unused rules in Style Sheets (CSS) can contribute to network payload sizes. Codehs.com should consider removing dead rules from style sheets and deferring the loading of CSS not used for above-the-fold content.
URL Transfer Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
261320
259111
https://www.youtube.com/s/player/408a20d8/www-player-webp.css
46436
46436
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.css
27932
26319
/*! * Font Awesome Free 5.15.3 by @fontawesome - https://fontawesome.com * License - https://fonta...
12328
12234
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/deferred_compressed.css
11484
11484
Preload Largest Contentful Paint image — Potential savings of 310 ms
It is recommended to preload images used by LCP elements, to improve LCP time.
URL Potential Savings (Ms)
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
310

Diagnostics

Avoid an excessive DOM size — 1,244 elements
A large DOM (Document Object Model) will increase memory usage, cause longer system calculations as well as costly layout reflows.
Statistic Element Value
Total DOM Elements
1244
Maximum DOM Depth
15
Maximum Child Elements
18

Metrics

Largest Contentful Paint — 5.5 s
The timing of the largest text or image that is painted.
Time to Interactive — 5.5 s
The time taken for the page to become fully interactive.
Total Blocking Time — 420 ms
The total blocking time is the sum of all time periods between First Contentful Paint and Time to Interactive (when task length exceeded 50ms).

Opportunities

Properly size images — Potential savings of 1,314 KiB
Images can slow down the page's load time. Codehs.com should consider serving more appropriate-sized images.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/img/homepage/editor.png
443653
309072
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
260934
223178
https://static.codehs.com/img/homepage/badge_collage.png
405403
199455
https://static.codehs.com/img/courses/micro_bit.png
174426
172856
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
118801
101611
https://static.codehs.com/img/courses/cyber_security.png
64602
60564
https://static.codehs.com/img/homepage/news/usa_today_logo.png
42121
40825
https://static.codehs.com/img/homepage/articles/fashion_retail.png
34186
29239
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
28053
https://static.codehs.com/img/courses/intro_cs.png
27621
27000
https://static.codehs.com/img/homepage/news/edweek_logo.png
35990
24882
https://static.codehs.com/img/marketing/pro_page/activities.png
28520
23365
https://static.codehs.com/img/courses/intro_python.png
22550
22198
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
23328
19111
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
24321
16379
https://static.codehs.com/img/homepage/news/edsurge_logo.png
23294
16104
https://static.codehs.com/img/logos/codehs_logo_dark_text.png
10879
9948
https://static.codehs.com/img/homepage/news/forbes_logo.png
11721
9185
https://static.codehs.com/img/homepage/pd.png
212209
7507
https://static.codehs.com/img/brand_logo.png
5481
4789
Defer offscreen images — Potential savings of 1,247 KiB
Time to Interactive can be slowed down by resources on the page. Codehs.com should consider lazy-loading offscreen and hidden images.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/img/homepage/badge_collage.png
405403
405403
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
260934
260934
https://static.codehs.com/img/homepage/pd.png
212209
212209
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
118801
118801
https://static.codehs.com/img/homepage/news/usa_today_logo.png
42121
42121
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
37404
https://static.codehs.com/img/homepage/news/edweek_logo.png
35990
35990
https://static.codehs.com/img/homepage/articles/fashion_retail.png
34186
34186
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
24321
24321
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
23328
23328
https://static.codehs.com/img/homepage/news/edsurge_logo.png
23294
23294
https://static.codehs.com/img/homepage/news/forbes_logo.png
11721
11721
https://static.codehs.com/img/logos/codehs_logo_white_text.png
10731
10731
https://uploads.codehs.com/b46469b780f8bb458a1728fc1c2e1497
9509
9509
https://static.codehs.com/img/program_icons/python.png
6054
6054
https://static.codehs.com/img/program_icons/java-console.png
5055
5055
https://static.codehs.com/img/homepage/news/today_logo.png
4668
4668
https://static.codehs.com/img/program_icons/graphics.png
3819
3819
https://static.codehs.com/img/program_icons/karel.png
3802
3802
https://static.codehs.com/img/program_icons/html.png
3191
3191
Reduce unused JavaScript — Potential savings of 1,380 KiB
It is advised to remove unused JavaScript in order to reduce bytes consumed by network activity.
URL Transfer Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
902886
552723
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
502685
355606
https://unpkg.com/tableexport.jquery.plugin/libs/jsPDF/jspdf.min.js
307808
241149
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
175315
146403
https://unpkg.com/tableexport.jquery.plugin/tableExport.min.js
43335
42305
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
65996
39539
https://js.intercomcdn.com/frame-modern.7401e6d2.js
69884
35743
Serve images in next-gen formats — Potential savings of 2,222 KiB
Consider JPEG 2000, JPEG XR or WebP image formats which provide better compression than PNG and JPEG.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
840728
820020
https://static.codehs.com/img/homepage/editor.png
443653
365069
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
260934
213358
https://static.codehs.com/img/homepage/pd.png
212209
191093
https://static.codehs.com/img/courses/micro_bit.png
174426
136802
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
118801
93959
https://static.codehs.com/img/homepage/badge_collage.png
405403
89577
https://static.codehs.com/img/courses/cyber_security.png
64602
53500
https://static.codehs.com/img/homepage/news/edweek_logo.png
35990
32326
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
32212
https://static.codehs.com/img/homepage/news/usa_today_logo.png
42121
30055
https://static.codehs.com/img/karel/default/karel_west.png?time=1627043525239
34741
24009
https://static.codehs.com/img/karel/default/karel_east.png?time=1627043525239
34493
23827
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
24321
23499
https://static.codehs.com/img/karel/default/karel_south.png?time=1627043525239
34079
23439
https://static.codehs.com/img/karel/default/karel_north.png?time=1627043525239
33777
23251
https://static.codehs.com/img/homepage/articles/fashion_retail.png
34186
21640
https://static.codehs.com/img/homepage/news/edsurge_logo.png
23294
21554
https://static.codehs.com/img/marketing/pro_page/activities.png
28520
13060
https://static.codehs.com/img/courses/intro_python.png
22550
12698
https://static.codehs.com/img/courses/intro_cs.png
27621
10111
https://static.codehs.com/img/homepage/news/forbes_logo.png
11721
10029
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
23328
9932
Preload key requests — Potential savings of 2,120 ms
Key requests can be preloaded by using '<link rel=preload>'. Codehs.com should consider using '<link rel=preload>' to prioritize fetching resources that are currently requested later in page load.
URL Potential Savings (Ms)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/deferred_compressed.css
2120
https://static.codehs.com/lib/video-js/video-js.min.css
2120
https://static.codehs.com/lib/jquery-ui/jquery-ui-1.8.18.custom.css
2120

Diagnostics

Avoid enormous network payloads — Total size was 5,733 KiB
Large network payloads can cost users money and are linked to long load times.
URL Transfer Size (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
902886
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
841143
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
502685
https://static.codehs.com/img/homepage/editor.png
444146
https://static.codehs.com/img/homepage/badge_collage.png
405896
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
261427
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
261320
https://static.codehs.com/img/homepage/pd.png
212702
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
175315
https://static.codehs.com/img/courses/micro_bit.png
174919
Serve static assets with an efficient cache policy — 27 resources found
Codehs.com can speed up repeat visits by increasing the cache lifetime, which is essentially how long before a cached copy expires.
URL Cache TTL (Ms) Transfer Size (Bytes)
https://static.codehs.com/img/homepage/news/usa_today_logo.png
0
42556
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
0
37838
https://static.codehs.com/img/homepage/news/edweek_logo.png
0
36425
https://static.codehs.com/img/karel/default/karel_west.png?time=1627043525239
0
35411
https://static.codehs.com/img/karel/default/karel_east.png?time=1627043525239
0
35163
https://static.codehs.com/img/karel/default/karel_south.png?time=1627043525239
0
34749
https://static.codehs.com/img/karel/default/karel_north.png?time=1627043525239
0
34447
https://static.codehs.com/font/fontawesome-webfont.woff
0
32525
https://static.codehs.com/img/courses/intro_cs.png
0
28056
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
0
24754
https://static.codehs.com/img/homepage/news/edsurge_logo.png
0
23727
https://static.codehs.com/img/homepage/news/forbes_logo.png
0
12156
https://static.codehs.com/audio/bark3.mp3
0
6778
https://static.codehs.com/img/program_icons/python.png
0
6488
https://static.codehs.com/img/brand_logo.png
0
5915
https://static.codehs.com/img/homepage/news/today_logo.png
0
5102
https://static.codehs.com/img/program_icons/graphics.png
0
4253
https://static.codehs.com/img/program_icons/karel.png
0
4236
https://static.codehs.com/img/program_icons/html.png
0
3625
https://static.codehs.com/lib/video-js/video-js.min.css
0
3116
https://bam-cell.nr-data.net/1/5c532d628b?a=2416009&v=1210.e2a3f80&to=ZgRWZ0tRXBJXBhINVl9OckZXU0YIWQtJB1ZDBBpFUFVFEgwMCABcSQ%3D%3D&rst=2011&ck=1&ref=https://codehs.com/&qt=1&ap=110&be=391&fe=1975&dc=1444&perf=%7B%22timing%22:%7B%22of%22:1627043524078,%22n%22:0,%22f%22:49,%22dn%22:49,%22dne%22:49,%22c%22:49,%22ce%22:49,%22rq%22:49,%22rp%22:135,%22rpe%22:135,%22dl%22:140,%22di%22:531,%22ds%22:1444,%22de%22:1462,%22dc%22:1974,%22l%22:1974,%22le%22:1978%7D,%22navigation%22:%7B%7D%7D&fp=552&fcp=552&jsonp=NREUM.setToken
0
877
https://js.intercomcdn.com/shim.latest.js
300000
6504
https://use.typekit.net/xdy5aym.js
600000
7247
https://static.doubleclick.net/instream/ad_status.js
900000
653
https://www.google-analytics.com/analytics.js
7200000
20313
https://js-agent.newrelic.com/nr-1210.min.js
7200000
12427
https://p.typekit.net/p.gif?s=1&k=xdy5aym&ht=tk&h=codehs.com&f=139.140.173.175.176.5474&a=1108077&js=1.20.0&app=typekit&e=js&_=1627043525480
604800000
350
Ensure text remains visible during webfont load
Make use of the font-display CSS feature, which will ensure text is user-visible while webfonts are loading.
URL Potential Savings (Ms)
https://static.codehs.com/font/fontawesome-webfont.woff
49.26300002262
https://fonts.gstatic.com/s/roboto/v18/KFOmCnqEu92Fr1Mu4mxKKTU1Kg.woff2
3.3760000951588
https://use.typekit.net/af/9b1c6c/00000000000000000001499c/21/l?subset_id=2&fvd=n7&v=3
76.45699987188
https://use.typekit.net/af/4b77d9/0000000000000000000148a9/21/l?subset_id=2&fvd=i7&v=3
83.835999947041
https://use.typekit.net/af/0e8ca9/0000000000000000000148a6/21/l?subset_id=2&fvd=n6&v=3
78.475999645889
https://use.typekit.net/af/651407/0000000000000000000148a4/21/l?subset_id=2&fvd=n4&v=3
27.119999751449
https://use.typekit.net/af/222d96/0000000000000000000148a5/21/l?subset_id=2&fvd=i4&v=3
33.078000415117
https://use.typekit.net/af/04aaaa/0000000000000000000148a2/21/l?subset_id=2&fvd=n3&v=3
87.034999858588
https://fonts.gstatic.com/s/roboto/v27/KFOmCnqEu92Fr1Mu4mxKKTU1Kg.woff2
3.0569997616112
Reduce the impact of third-party code — Third-party code blocked the main thread for 260 ms
It is advised to either limit, remove or delay the loading of redundant third-party code which may be significantly impacting load performance.
Third-Party Transfer Size (Bytes) Main-Thread Blocking Time (Ms)
649984
257.834
119110
1.152
841143
0
183498
0
114282
0
113173
0
38940
0
24584
0
22413
0
20949
0
18654
0
13304
0
6306
0
1382
0
Some third-party resources can be lazy loaded with a facade — 2 facade alternatives available
Consider replacing third-party embeds with a facade until they are required (use lazy loading).
Product Transfer Size (Bytes) Main-Thread Blocking Time (Ms)
YouTube Embedded Player (Video)
649984
257.834
Intercom Widget (Customer Success)
119110
1.152
Does not use passive listeners to improve scrolling performance
Improve the page's scroll performance by marking touch and wheel event listeners as 'passive'.
Source
Image elements do not have explicit `width` and `height`
Reduce layout shifts and improve CLS by setting explicit width and height properties on image elements.
URL Failing Elements
https://static.codehs.com/img/homepage/editor.png
img
https://static.codehs.com/img/homepage/badge_collage.png
img
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
img
https://static.codehs.com/img/homepage/pd.png
img
https://static.codehs.com/img/courses/micro_bit.png
img
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
img
https://static.codehs.com/img/courses/cyber_security.png
img
https://static.codehs.com/img/homepage/articles/fashion_retail.png
img
https://static.codehs.com/img/marketing/pro_page/activities.png
img
https://static.codehs.com/img/courses/intro_cs.png
img
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
img
https://static.codehs.com/img/courses/intro_python.png
img
https://static.codehs.com/img/logos/codehs_logo_dark_text.png
https://static.codehs.com/img/brand_logo.png
img
https://static.codehs.com/img/marketing/icons/chevron-left.png
img
https://static.codehs.com/img/marketing/icons/chevron-left.png
img
88

Accessibility

Indicates how accessible the page is and highlights opportunities where the page can be made more accessible to users of codehs.com. This includes details about various page attributes that can be optimized.

Navigation

`[accesskey]` values are unique
Access keys assist users with focusing on different parts of the page. Each access key should be unique for proper navigation.
The page contains a heading, skip link, or landmark region
It is advised to provide ways to bypass repetitive content, allowing users to navigate the page efficiently.
`[id]` attributes on active, focusable elements are unique
Ensure all focusable elements have a unique id value to allow them to be visible to users of assistive technologies, like a screen reader.
Heading elements appear in a sequentially-descending order
Properly order all headers and do not skip heading levels to better the navigation and readability for users of assistive technologies, like a screen reader.
No element has a `[tabindex]` value greater than 0
Although technically valid, a tabindex value greater than 0 often creates frustrating experiences for users who rely on assistive technologies.

ARIA

`[aria-*]` attributes match their roles
Avoid mismatching 'aria-*' attributes and their 'role' value, as it invalidates the attribute.
`button`, `link`, and `menuitem` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
`[aria-hidden="true"]` is not present on the document `<body>`
If aria-hidden=true is set on the document body, assistive technologies, like a screen reader will work inconsistently.
`[aria-hidden="true"]` elements do not contain focusable descendents
Interactive elements within an aria-hidden=true element are unavailable to users of assistive technologies, like a screen reader.
ARIA input fields have accessible names
Generic names are announced to users of assistive technologies, like a screen reader, when an input field does not have an accessible name specified.
ARIA `meter` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
ARIA `progressbar` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
`[role]`s have all required `[aria-*]` attributes
Some ARIA roles have required 'aria-*' attributes, which provide essential information about state and functionality.
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
Some ARIA parent roles cannot perform their intended functions if specific child roles are not used.
`[role]`s are contained by their required parent element
Some ARIA child roles cannot perform their intended functions if specific parent roles are not used.
`[role]` values are valid
All ARIA roles require valid values to perform their intended functions.
ARIA toggle fields have accessible names
Generic names are announced to users of assistive technologies, like a screen reader, when a toggle field does not have an accessible name specified.
ARIA `tooltip` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
ARIA `treeitem` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
`[aria-*]` attributes have valid values
ARIA attributes cannot be interpreted with invalid values when used by screen readers and other assistive technologies.
`[aria-*]` attributes are valid and not misspelled
ARIA attributes cannot be interpreted with invalid names when used by screen readers and other assistive technologies.
ARIA IDs are unique
Ensure all ARIA ID values are unique to prevent elements from being overlooked by assistive technologies, like a screen reader.

Names and labels

Buttons have an accessible name
Buttons become unusable as they are announced simply as "button" when the button does not have an accessible name, when used by screen readers and other assistive technologies.
Document has a `<title>` element
Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
No form fields have multiple labels
Having multiple labels for form fields can be confusing to assistive technologies, like a screen reader.
`<frame>` or `<iframe>` elements have a title
Screen reader users and other assistive technology users rely on frame titles to describe the contents of frames.
`<input type="image">` elements have `[alt]` text
Input buttons with alternative text assist screen readers and other assistive technology users to understand its purpose.
Form elements have associated labels
Screen readers and other assistive technologies rely on labels to properly announce form controls.
`<object>` elements have `[alt]` text
It is advised that alt text is used on '<object>' elements in order to provide meaning to screen reader and other assistive technology users, as these technologies are unable to translate non-text content.

Tables and lists

`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Screen readers and other assistive technologies may produce poor and inaccurate output when definition lists are not properly marked up.
Definition list items are wrapped in `<dl>` elements
In order for screen readers and other assistive technologies to properly announce definition list items ('<dt>' and '<dd>'), they must be wrapped in parent a '<dl>' element.
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
Use proper list structure to aid screen readers and other assistive technologies.
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
In order for screen readers to announce list items, ensure that list items ('<li>') are contained within parent '<ul>' or '<ol>' tags.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that '<td>' cells using the headers attribute only refer to other cells in the same table, to improve screen reader user experience.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that table headers refer to some set of cells, to improve screen reader user experience.

Internationalization and localization

`<html>` element has a `[lang]` attribute
It is advised to provide a lang attribute so that screen readers and other assistive technologies are guaranteed to announce the page's text correctly. When not provided, the user's default language setting will be used which may cause inaccuracies.
`<html>` element has a valid value for its `[lang]` attribute
Specify a valid BCP 47 language in order to help screen readers and other assistive technologies announce text properly.
`[lang]` attributes have a valid value
Specify a valid BCP 47 language on elements in order to help screen readers and other assistive technologies announce text properly.

Best practices

The document does not use `<meta http-equiv="refresh">`
Pages that refresh automatically cause a poor user experience as focus is directed back to the top of the page unexpectedly.
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
For users with low vision who rely on screen magnification, ensure that zooming is not disabled.

Audio and video

`<video>` elements contain a `<track>` element with `[kind="captions"]`
Codehs.com may provide assistance to deaf or hearing-impaired users with captions on videos.

Contrast

Names and labels

Image elements do not have `[alt]` attributes
Provide short and descriptive alternative text where possible on informative elements.
Failing Elements
img
img
img
img
img
img
img
img
img
img
img
img
img
img
Links do not have a discernible name
In order to improve the navigation for screen reader and other assistive technology users, use link text that is unique, focusable and discernible.

Manual Checks

The page has a logical tab order
The visual layout should be logical in its tab order and users cannot focus elements that are offscreen.
Interactive controls are keyboard focusable
Ensure that custom interactive controls are keyboard focusable and that a focus indicator is displayed.
Interactive elements indicate their purpose and state
Ensure that interactive elements (such as links and buttons) are distinguishable from non-interactive elements and that they indicate their state.
The user's focus is directed to new content added to the page
When new content (such as a dialogue) is added to the page, the user's focus should be directed to it.
User focus is not accidentally trapped in a region
Avoid focus being accidentally trapped when a user tabs in and out of controls or regions on page.
Custom controls have associated labels
Ensure that custom interactive controls have associated labels, which are provided by aria-label and aria-labelledby attributes.
Custom controls have ARIA roles
Ensure that all custom interactive controls have appropriate ARIA roles.
Visual order on the page follows DOM order
Ensure that the DOM order matches with the page's visual order, in order to improve navigation for screen readers and other assistive technologies.
Offscreen content is hidden from assistive technology
Ensure that offscreen content is hidden through the use of "display:none" styling or the aria-hidden attribute.
HTML5 landmark elements are used to improve navigation
Elements such as <main> and <nav> are recommended as they are used by screen readers and other assistive technologies to improve keyboard navigation.
67

Best Practices

Indicates the recommended, best practices currently in place on the page and highlights the best practices that codehs.com should incorporate. This includes practices such as protecting pages with HTTPS.

Audits

Avoids requesting the geolocation permission on page load
When requesting a user's location, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Avoids requesting the notification permission on page load
When requesting permission to send notifications, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Ensure CSP is effective against XSS attacks
Significantly reduce the risk of cross-site scripting attacks (XSS) by ensuring you have a strong Content Security Policy (CSP).
Description Directive Severity
No CSP found in enforcement mode
High

Audits

Allows users to paste into password fields
Ensure that password inputs may be pasted into to aid in the user's ability to use password managers and improve security.
Displays images with correct aspect ratio
Ensure that image display dimensions match their natural aspect ratio.
Serves images with appropriate resolution
For maximum image clarity, ensure images have natural dimensions and are proportional to the display size and pixel ratio.
Fonts with `font-display: optional` are preloaded
It is recommended that optional fonts are preloaded.

Audits

Page has the HTML doctype
Ensure a doctype is specified to prevent the browser from switching to quirks-mode.
Properly defines charset
It is advised to declare a character encoding, optionally via a <meta> tag in the first 1024 bytes of the HTML or in the Content-Type HTTP response header.

Audits

Avoids Application Cache
Application cache is deprecated and is no longer recommended.
Detected JavaScript libraries
Below is a list of all front-end JavaScript libraries that were detected on the page.
Name Version
jQuery
2.2.4
jQuery UI
1.10.1
Lo-Dash
3.10.1
Handlebars
4.7.2
WebFont Loader
Moment.js
2.24.0
Moment Timezone
0.4.1
core-js
core-js-global@3.8.1; core-js-global@3.1.3; core-js-global@3.1.3; core-js-global@3.1.3
Avoids deprecated APIs
Avoid deprecated APIs which will eventually be removed the browser.
No issues in the `Issues` panel in Chrome Devtools
There may be unresolved issues logged to Chrome Devtools.

Audits

Does not use HTTPS — 1 insecure request found
Ensure that all pages are protected with HTTPS (including those that do not handle sensitive data) as HTTPS prevents tampering and passive listening on communications between the app and its users. Additionally, HTTPS is a prerequisite for HTTP/2 and many new web platform APIs.
Insecure URL Request Resolution
http://codehs.com/
Allowed
Includes front-end JavaScript libraries with known security vulnerabilities — 16 vulnerabilities detected
Ensure that the use of third-party scripts is minimal and that only trusted third-party scripts are used as some may contain known security vulnerabilities which may be exploited by attackers.
Library Version Vulnerability Count Highest Severity
4
Medium
1
High
9
High
2
Medium

Audits

Registers an `unload` listener
The 'unload' event does not fire reliably, causing issues with browser optimizations such as the Back-Forward Cache. It is recommended that 'pagehide' or 'visibilitychange' events are used instead.
Source
Browser errors were logged to the console
Below is a list of all errors logged to the console, which indicate unresolved problems on the site.
Source Description
WebSocket connection to 'wss://nexus-websocket-a.intercom.io/pubsub/5-WX0-TLGc2vensnTGyZY6MGKHJoM2BnUxdI5NsJIJ9rbMywN32px0m1j1-vFgTMhwpF8aaDuOa9xmQelZ6FxKFXAnUrB6RLe4EHnt?X-Nexus-New-Client=true&X-Nexus-Version=0.8.5&user_role=undefined' failed: Error in connection establishment: net::ERR_NAME_NOT_RESOLVED
Missing source maps for large first-party JavaScript
Consider deploying source maps for added benefits such as the ability to debug while in production.
URL Map URL
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
64

SEO

Indicates how well the page is optimized for ranking in search engines and highlights Search Engine Optimization (SEO) opportunities for codehs.com. This includes optimizations such as providing meta data.

Mobile Friendly

Has a `<meta name="viewport">` tag with `width` or `initial-scale`
It is advised to use a '<meta name="viewport">' tag for the optimization of codehs.com on mobile screens.
Document uses legible font sizes
Font sizes of 12px or less are too small to most mobile users without user gestures and further action. Aim for more than 60% of page text to use font sizes greater than 12px.
Tap targets are sized appropriately
Interactive elements (such as buttons and links) should be appropriately spaced, sized and easy enough to select or tap with regard to their surrounding elements.

Content Best Practices

Document has a `<title>` element
Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
Document has a valid `hreflang`
Search engines can be instructed to list specific versions of a page for a given language or region through the use of hreflang links.
Document has a valid `rel=canonical`
Search engines can be suggested which URL should be shown in search results through the use of canonical links.
Document avoids plugins
The content of plugins cannot be indexed by search engines and many devices either restrict or do not support them.

Crawling and Indexing

Page has successful HTTP status code
Avoid pages with unsuccessful HTTP status codes as they may not be indexed by search engines.
Page isn’t blocked from indexing
Pages that cannot be crawled by search engines cannot be indexed or included in their search results. Ensure that search engines have permission to crawl all pages that should be indexed.
robots.txt is valid
Malformed robots.txt files prevent crawlers from understanding how a site wants to be crawled or indexed, which can be devastating to SEO.

Content Best Practices

Document does not have a meta description
Meta descriptions may be used by search engines when displaying a link to the page and should concisely summarize the page's content.
Links do not have descriptive text — 7 links found
Make use of descriptive link text to assist search engines in understanding the content.
Image elements do not have `[alt]` attributes
Provide short and descriptive alternative text where possible on informative elements.
Failing Elements
img
img
img
img
img
img
img
img
img
img
img
img
img
img

Crawling and Indexing

Links are not crawlable
Ensure that the 'href' attribute of anchor elements links to the appropriate destination. This allows for more pages of the site to be discovered by search engines.

Manual Checks

Structured data is valid
Structured data can be validated through the use of the Structured Data Testing Tool and the Structured Data Linter.
45

Progressive Web App

Indicates how valid the aspects of a Progressive Web App (PWA) are for the page and highlights opportunities to enable/improve the PWA of codehs.com. This includes details about web app manifests.

PWA Optimized

Redirects HTTP traffic to HTTPS
It is advised to redirect all HTTP traffic to HTTPS, in order to enable secure web features for all users.
Content is sized correctly for the viewport
Ensure that the width of the app's content matches the width of the viewport, otherwise the app might not be optimized for mobile screens.
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
It is advised to use a '<meta name="viewport">' tag for the optimization of codehs.com on mobile screens.
Provides a valid `apple-touch-icon`
iOS users of Progressive Web Apps will benefit from an apple touch icon, which can be defined with 'apple-touch-icon', which must point to a non-transparent 192px (or 180px) square PNG.

Installable

Web app manifest or service worker do not meet the installability requirements — 1 reason
User engagement may be increased by leveraging the browsers ability to proactively prompt users to add the app to their homescreen.
Failure reason
No manifest was fetched

PWA Optimized

Does not register a service worker that controls page and `start_url`
A service worker is used to provide Progressive Web Apps the use of features such as working offline, the ability for the app to be added to the homescreen as well as push notifications.
Is not configured for a custom splash screen
Themed splash screens ensure a high-quality user experience at launch for app users.
View Data
Does not set a theme color for the address bar.
A theme may be applied to the browser address bar, which ideally can be made to match the site.
View Data
Manifest doesn't have a maskable icon
Maskable icons are great to ensure that images fill the entire shape when installing the app on a device.

Manual Checks

Site works cross-browser
Ensure that the Progressive Web App works correctly across every major browser.
Page transitions don't feel like they block on the network
Users perceive apps with responsive, snappy transitions as higher peforming and ensures a great user experience, even on a slow network.
Each page has a URL
Ensure that all pages are deep linkable via URL. They should also be unique for the purpose of shareability on social media.
Avg. (All Categories) 53
Performance 5
Accessibility 87
Best Practices 67
SEO 65
Progressive Web App 42
0–49 (Fail) 50–89 (Average) 90–100 (Pass)
URL: https://codehs.com/
Updated: 23rd July, 2021

3.04 seconds
First Contentful Paint (FCP)
48%
31%
21%

0.04 seconds
First Input Delay (FID)
85%
9%
6%

Simulate loading on mobile
5

Performance

Indicates how well the page is performing and highlights opportunities where performance may be improved for codehs.com. This includes details about optimizing page load times which can result in a better user experience.

Opportunities

Minify CSS
Cascading Style Sheets (CSS) files can contribute to network payload sizes. Codehs.com should consider minifying CSS files.
Minify JavaScript
JavaScript (JS) files can contribute to network payload sizes and increase script parse times. Codehs.com should consider minifying JS files.
Enable text compression
Text-based resources should be served with compression, such as gzip, deflate or brotli.
Preconnect to required origins
Resource hints, such as 'preconnect' or 'dns-prefetch', may assist in establishing early connections to important third-party origins.
Initial server response time was short — Root document took 90 ms
It is advised to keep the server response time short for the main document, because all other requests depend on it.
URL Time Spent (Ms)
https://codehs.com/
85.961
Avoid multiple page redirects — Potential savings of 630 ms
Redirects can cause additional delays before the page can begin loading. Codehs.com should avoid multiple or unnecessary page redirects.
URL Time Spent (Ms)
http://codehs.com/
630
https://codehs.com/
0
Preload key requests
Key requests can be preloaded by using '<link rel=preload>'. Codehs.com should consider using '<link rel=preload>' to prioritize fetching resources that are currently requested later in page load.
Use video formats for animated content
Large GIFs are inefficient for delivering animated content. It is recommended to use MPEG4/WebM videos for animations and PNG/WebP for static images instead of GIF.
Remove duplicate modules in JavaScript bundles
Ensure that no duplicate JavaScript modules from bundles exist to reduce bytes consumed by network activity.
Avoid serving legacy JavaScript to modern browsers — Potential savings of 20 KiB
Polyfills and transforms enable legacy browsers to use new JavaScript features. For bundled JavaScript it is recommended to adopt a modern script deployment strategy using module/nomodule feature detection. This will reduce the amount of code shipped to modern browsers.
URL Potential Savings (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
10184
https://unpkg.com/tableexport.jquery.plugin@1.10.26/libs/jsPDF/jspdf.min.js
10068
https://js.intercomcdn.com/vendor-modern.0c2722c5.js
104
https://unpkg.com/tableexport.jquery.plugin@1.10.26/libs/jsPDF-AutoTable/jspdf.plugin.autotable.js
56

Diagnostics

Avoid chaining critical requests — 12 chains found
Below is a list of Critical Request Chains, which shows which resources are loaded with a high priority. Codehs.com should consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.
User Timing marks and measures — 4 user timings
Make use of the User Timing API to measure an app's real-world performance during key user experiences.
Name Type Start Time (Ms) Duration (Ms)
mark_pe
Mark
1791.938
mark_fs
Mark
1869.396
mark_qoes
Mark
1889.77
mark_ol
Mark
2316.42
Keep request counts low and transfer sizes small — 98 requests • 5,733 KiB
It is advised to add a budgets.json file in order to set budgets for the quantity and size of page resources.
Resource Type Requests Transfer Size (Bytes)
Total
98
5870856
Image
37
3050343
Script
25
2017306
Stylesheet
8
359431
Font
11
318747
Document
3
88226
Other
13
30025
Media
1
6778
Third-party
53
2168300
Largest Contentful Paint element — 1 element found
The element which was identified as the Largest Contentful Paint.
Element
Avoid large layout shifts — 3 elements found
Below is a list of all DOM elements that contribute to the CLS of the page.
Element CLS Contribution
0.378125
0.0890625
svg
0.020833333333333
Avoids `document.write()`
Avoid or limit the use of external scripts that are dynamically injected via 'document.write()' as users on slow connections will be delayed by tens of seconds.
Avoid long main-thread tasks — 20 long tasks found
Below is a list of the longest tasks on the main thread, which is useful when identifying the worst input delay contributors.
URL Start Time (Ms) Duration (Ms)
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
16505
995
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Avoid non-composited animations
It is recommended to avoid non-composited animations which are often janky and increase CLS.

Budgets

Performance budget
It is advised to keep the quantity and size of all network requests under the targets set by the provided performance budget.
Timing budget
It is advised to set a timing budget to monitor the performance of your site.

Other

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Image
https://js.intercomcdn.com/shim.latest.js
h2
2316.366000101
2335.6940001249
6503
18297
200
application/javascript
Script
https://bam-cell.nr-data.net/1/5c532d628b?a=2416009&v=1210.e2a3f80&to=ZgRWZ0tRXBJXBhINVl9OckZXU0YIWQtJB1ZDBBpFUFVFEgwMCABcSQ%3D%3D&rst=2339&ck=1&ref=https://codehs.com/&qt=1&ap=110&be=449&fe=2056&dc=1425&perf=%7B%22timing%22:%7B%22of%22:1627043551111,%22n%22:0,%22f%22:54,%22dn%22:54,%22dne%22:54,%22c%22:54,%22ce%22:54,%22rq%22:54,%22rp%22:140,%22rpe%22:140,%22dl%22:145,%22di%22:636,%22ds%22:1424,%22de%22:1447,%22dc%22:2054,%22l%22:2054,%22le%22:2063%7D,%22navigation%22:%7B%7D%7D&fp=634&fcp=634&jsonp=NREUM.setToken
http/1.1
2339.9600000121
2472.0350001007
877
49
200
text/javascript
Script
https://js.intercomcdn.com/frame-modern.7401e6d2.js
h2
2357.669999823
2375.2000001259
69884
260239
200
application/javascript
Script
https://js.intercomcdn.com/vendor-modern.0c2722c5.js
h2
2358.0060000531
2371.0500001907
39135
127366
200
application/javascript
Script
https://api-iam.intercom.io/messenger/web/ping
h2
2463.5450001806
3462.3719998635
3183
9299
200
application/json
XHR
https://www.youtube.com/youtubei/v1/log_event?alt=json&key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8
h2
4156.9799999706
4170.735000167
512
28
200
application/json
XHR
Network Round Trip Times — 0 ms
High Network RTT (Round Trip Times) can have a large impact on performance. Providing servers geographically closer to the user could improve performance.
Server Backend Latencies — 0 ms
High server latencies indicate the server is overloaded or has a poor backend performance.
Tasks
Below is a list of the top-level main thread tasks that executed during page load.
Start Time (Ms) End Time (Ms)
149.467
6.761
156.799
5.24
168.726
5.746
186.243
10.999
238.334
9.711
249.835
9.354
382.647
65.963
450.361
32.868
483.24
147.433
635.28
67.258
716.71
5.659
724.114
8.198
732.324
6.425
744.587
17.404
766.897
152.826
920.612
7.138
927.768
5.417
933.703
23.381
962.028
492.281
1454.353
5.29
1478.281
22.697
1510.938
24.976
1537.982
10.194
1563.281
27.661
1605.968
17.432
1632.973
7.315
1642.669
6.857
1657.072
12.805
1672.852
25.399
1698.863
124.173
1829.107
191.819
2028.223
9.135
2043.051
11.665
2054.733
14.511
2072.158
248.843
2324.914
7.605
2338.085
10.053
2351.403
15.067
2367.646
8.201
2396.023
78.046
3470.701
29.101
4059.375
105.422
4167.159
12.371
Diagnostics
Below is a collection of useful page vitals.
View Data
Metrics
Below is a collection of metrics.
View Data
Script Treemap Data
Provide as required, for treemap app.

Opportunities

Efficiently encode images — Potential savings of 25 KiB
Unoptimized images can consume more cellular data than what is necessary.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
25842

Diagnostics

Avoid an excessive DOM size — 1,245 elements
A large DOM (Document Object Model) will increase memory usage, cause longer system calculations as well as costly layout reflows.
Statistic Element Value
Total DOM Elements
1245
Maximum DOM Depth
15
Maximum Child Elements
18

Metrics

First Contentful Paint — 5.0 s
The time taken for the first image or text on the page to be rendered.
Speed Index — 11.6 s
The time taken for the page contents to be visibly populated.
Largest Contentful Paint — 28.7 s
The timing of the largest text or image that is painted.
Time to Interactive — 29.8 s
The time taken for the page to become fully interactive.
Total Blocking Time — 3,580 ms
The total blocking time is the sum of all time periods between First Contentful Paint and Time to Interactive (when task length exceeded 50ms).
Cumulative Layout Shift — 0.488
Cumulative Layout Shift is the measurement of visible elements collective movement within the viewport.
View Data

Other

Max Potential First Input Delay — 1,000 ms
Users could experience a delay when interacting with the page.
First Meaningful Paint — 5.0 s
The time taken for the primary content of the page to be rendered.
First Contentful Paint (3G) — 10590 ms
The time taken for the first image or text on the page to be rendered while on a 3G network.

Opportunities

Eliminate render-blocking resources — Potential savings of 1,950 ms
Resources, such as JavaScript and style sheets, can block the first paint of the page. Codehs.com should consider delivering critical JavaScript/style sheets (JS/CSS) inline and deferring all non-critical JS/CSS.
URL Transfer Size (Bytes) Potential Savings (Ms)
https://cdn.jsdelivr.net/gh/kenwheeler/slick@1.8.1/slick/slick.css
1382
780
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.css
27932
1230
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
261320
2250
https://kit.fontawesome.com/9f6f20dc9f.js
4706
930
Properly size images — Potential savings of 745 KiB
Images can slow down the page's load time. Codehs.com should consider serving more appropriate-sized images.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/img/homepage/editor.png
443653
191098
https://static.codehs.com/img/courses/micro_bit.png
174426
163608
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
260934
148159
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
118801
67456
https://static.codehs.com/img/courses/cyber_security.png
64602
36780
https://static.codehs.com/img/homepage/news/usa_today_logo.png
42121
33188
https://static.codehs.com/img/courses/intro_cs.png
27621
23339
https://static.codehs.com/img/homepage/badge_collage.png
405403
20510
https://static.codehs.com/img/courses/intro_python.png
22550
20122
https://static.codehs.com/img/homepage/articles/fashion_retail.png
34186
19411
https://static.codehs.com/img/marketing/pro_page/activities.png
28520
18984
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
23328
15528
https://static.codehs.com/img/logos/codehs_logo_dark_text.png
10879
4461
Defer offscreen images — Potential savings of 1,557 KiB
Time to Interactive can be slowed down by resources on the page. Codehs.com should consider lazy-loading offscreen and hidden images.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/img/homepage/badge_collage.png
405403
405403
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
260934
260934
https://static.codehs.com/img/homepage/pd.png
212209
212209
https://static.codehs.com/img/courses/micro_bit.png
174426
174426
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
118801
118801
https://static.codehs.com/img/courses/cyber_security.png
64602
64602
https://static.codehs.com/img/homepage/news/usa_today_logo.png
42121
42121
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
37404
https://static.codehs.com/img/homepage/news/edweek_logo.png
35990
35990
https://static.codehs.com/img/homepage/articles/fashion_retail.png
34186
34186
https://static.codehs.com/img/marketing/pro_page/activities.png
28520
28520
https://static.codehs.com/img/courses/intro_cs.png
27621
27621
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
24321
24321
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
23328
23328
https://static.codehs.com/img/homepage/news/edsurge_logo.png
23294
23294
https://static.codehs.com/img/courses/intro_python.png
22550
22550
https://static.codehs.com/img/homepage/news/forbes_logo.png
11721
11721
https://static.codehs.com/img/logos/codehs_logo_white_text.png
10731
10731
https://uploads.codehs.com/b46469b780f8bb458a1728fc1c2e1497
9509
9509
https://static.codehs.com/img/program_icons/python.png
6054
6054
https://static.codehs.com/img/program_icons/java-console.png
5055
5055
https://static.codehs.com/img/homepage/news/today_logo.png
4668
4668
https://static.codehs.com/img/program_icons/graphics.png
3819
3819
https://static.codehs.com/img/program_icons/karel.png
3802
3802
https://static.codehs.com/img/program_icons/html.png
3191
3191
Reduce unused CSS — Potential savings of 348 KiB
Dead and/or unused rules in Style Sheets (CSS) can contribute to network payload sizes. Codehs.com should consider removing dead rules from style sheets and deferring the loading of CSS not used for above-the-fold content.
URL Transfer Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
261320
259128
https://www.youtube.com/s/player/408a20d8/www-player.css
46436
46436
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.css
27932
26778
/*! * Font Awesome Free 5.15.3 by @fontawesome - https://fontawesome.com * License - https://fonta...
12328
12212
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/deferred_compressed.css
11443
11443
Reduce unused JavaScript — Potential savings of 1,382 KiB
It is advised to remove unused JavaScript in order to reduce bytes consumed by network activity.
URL Transfer Size (Bytes) Potential Savings (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
902886
552723
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
502685
358419
https://unpkg.com/tableexport.jquery.plugin/libs/jsPDF/jspdf.min.js
307808
241149
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
175315
146403
https://unpkg.com/tableexport.jquery.plugin/tableExport.min.js
43335
42305
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
65872
38602
https://js.intercomcdn.com/frame-modern.7401e6d2.js
69884
35888
Serve images in next-gen formats — Potential savings of 2,222 KiB
Consider JPEG 2000, JPEG XR or WebP image formats which provide better compression than PNG and JPEG.
URL Resource Size (Bytes) Potential Savings (Bytes)
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
840728
820020
https://static.codehs.com/img/homepage/editor.png
443653
365069
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
260934
213358
https://static.codehs.com/img/homepage/pd.png
212209
191093
https://static.codehs.com/img/courses/micro_bit.png
174426
136802
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
118801
93959
https://static.codehs.com/img/homepage/badge_collage.png
405403
89577
https://static.codehs.com/img/courses/cyber_security.png
64602
53500
https://static.codehs.com/img/homepage/news/edweek_logo.png
35990
32326
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
37404
32212
https://static.codehs.com/img/homepage/news/usa_today_logo.png
42121
30055
https://static.codehs.com/img/karel/default/karel_west.png?time=1627043552420
34741
24009
https://static.codehs.com/img/karel/default/karel_east.png?time=1627043552420
34493
23827
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
24321
23499
https://static.codehs.com/img/karel/default/karel_south.png?time=1627043552420
34079
23439
https://static.codehs.com/img/karel/default/karel_north.png?time=1627043552420
33777
23251
https://static.codehs.com/img/homepage/articles/fashion_retail.png
34186
21640
https://static.codehs.com/img/homepage/news/edsurge_logo.png
23294
21554
https://static.codehs.com/img/marketing/pro_page/activities.png
28520
13060
https://static.codehs.com/img/courses/intro_python.png
22550
12698
https://static.codehs.com/img/courses/intro_cs.png
27621
10111
https://static.codehs.com/img/homepage/news/forbes_logo.png
11721
10029
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
23328
9932
Preload Largest Contentful Paint image — Potential savings of 1,830 ms
It is recommended to preload images used by LCP elements, to improve LCP time.
URL Potential Savings (Ms)
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
1830

Diagnostics

Avoid enormous network payloads — Total size was 5,733 KiB
Large network payloads can cost users money and are linked to long load times.
URL Transfer Size (Bytes)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
902886
https://codehsstatic.s3-us-west-2.amazonaws.com/img/homepage/cover.png
841143
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
502685
https://static.codehs.com/img/homepage/editor.png
444146
https://static.codehs.com/img/homepage/badge_collage.png
405896
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
261427
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
261320
https://static.codehs.com/img/homepage/pd.png
212702
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
175315
https://static.codehs.com/img/courses/micro_bit.png
174919
Serve static assets with an efficient cache policy — 27 resources found
Codehs.com can speed up repeat visits by increasing the cache lifetime, which is essentially how long before a cached copy expires.
URL Cache TTL (Ms) Transfer Size (Bytes)
https://static.codehs.com/img/homepage/news/usa_today_logo.png
0
42556
https://static.codehs.com/img/homepage/news/wsj_logo.jpg
0
37840
https://static.codehs.com/img/homepage/news/edweek_logo.png
0
36425
https://static.codehs.com/img/karel/default/karel_west.png?time=1627043552420
0
35411
https://static.codehs.com/img/karel/default/karel_east.png?time=1627043552420
0
35163
https://static.codehs.com/img/karel/default/karel_south.png?time=1627043552420
0
34749
https://static.codehs.com/img/karel/default/karel_north.png?time=1627043552420
0
34447
https://static.codehs.com/font/fontawesome-webfont.woff
0
32525
https://static.codehs.com/img/courses/intro_cs.png
0
28056
https://static.codehs.com/img/homepage/news/techcrunch_logo.png
0
24756
https://static.codehs.com/img/homepage/news/edsurge_logo.png
0
23729
https://static.codehs.com/img/homepage/news/forbes_logo.png
0
12156
https://static.codehs.com/audio/bark3.mp3
0
6778
https://static.codehs.com/img/program_icons/python.png
0
6488
https://static.codehs.com/img/brand_logo.png
0
5915
https://static.codehs.com/img/homepage/news/today_logo.png
0
5102
https://static.codehs.com/img/program_icons/graphics.png
0
4253
https://static.codehs.com/img/program_icons/karel.png
0
4236
https://static.codehs.com/img/program_icons/html.png
0
3625
https://static.codehs.com/lib/video-js/video-js.min.css
0
3116
https://bam-cell.nr-data.net/1/5c532d628b?a=2416009&v=1210.e2a3f80&to=ZgRWZ0tRXBJXBhINVl9OckZXU0YIWQtJB1ZDBBpFUFVFEgwMCABcSQ%3D%3D&rst=2339&ck=1&ref=https://codehs.com/&qt=1&ap=110&be=449&fe=2056&dc=1425&perf=%7B%22timing%22:%7B%22of%22:1627043551111,%22n%22:0,%22f%22:54,%22dn%22:54,%22dne%22:54,%22c%22:54,%22ce%22:54,%22rq%22:54,%22rp%22:140,%22rpe%22:140,%22dl%22:145,%22di%22:636,%22ds%22:1424,%22de%22:1447,%22dc%22:2054,%22l%22:2054,%22le%22:2063%7D,%22navigation%22:%7B%7D%7D&fp=634&fcp=634&jsonp=NREUM.setToken
0
877
https://js.intercomcdn.com/shim.latest.js
300000
6503
https://use.typekit.net/xdy5aym.js
600000
7247
https://static.doubleclick.net/instream/ad_status.js
900000
653
https://www.google-analytics.com/analytics.js
7200000
20313
https://js-agent.newrelic.com/nr-1210.min.js
7200000
12428
https://p.typekit.net/p.gif?s=1&k=xdy5aym&ht=tk&h=codehs.com&f=139.140.173.175.176.5474&a=1108077&js=1.20.0&app=typekit&e=js&_=1627043552660
604800000
350
Reduce JavaScript execution time — 5.3 s
JavaScript (JS) execution time can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
URL Total CPU Time (Ms) Script Evaluation (Ms) Script Parse (Ms)
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
1939.636
1379.628
249.916
https://codehs.com/
1836.344
55.264
12.472
https://www.youtube.com/s/player/408a20d8/player_ias.vflset/en_US/base.js
1459.152
1182.408
176.564
https://www.youtube.com/s/player/408a20d8/www-embed-player.vflset/www-embed-player.js
1413.4
957.93199999999
19.308
Unattributable
819.044
47.112
0.744
https://js.intercomcdn.com/frame-modern.7401e6d2.js
477.068
418.764
19.572
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/imports.css
263.852
0
0
https://www.youtube.com/embed/VXKG_VtR3Yc?rel=0&showinfo=0
201.028
111.32
15.624
https://unpkg.com/tableexport.jquery.plugin/libs/jsPDF/jspdf.min.js
187.9
160.672
27.228
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
142.352
95.896
46.456
https://www.googletagmanager.com/gtag/js?id=AW-982588809
137.364
125.244
11.464
https://kit.fontawesome.com/9f6f20dc9f.js
103.068
93.472
4.832
https://www.google-analytics.com/analytics.js
97.008
61.232
5.644
https://widget.intercom.io/widget/x13jbr4h
56.74
45.676
9.088
https://www.youtube.com/s/player/408a20d8/www-player.css
51.22
0
0
Minimize main-thread work — 9.5 s
Main-thread work timing can be lowered by reducing the time required for parsing, compiling and executing JS. Delivering smaller JS payloads may help with this.
Category Time Spent (Ms)
Script Evaluation
4865.736
Other
1873.516
Style & Layout
885.232
Script Parsing & Compilation
665.504
Parse HTML & CSS
526.828
Garbage Collection
485.404
Rendering
189.408
Ensure text remains visible during webfont load
Make use of the font-display CSS feature, which will ensure text is user-visible while webfonts are loading.
URL Potential Savings (Ms)
https://static.codehs.com/font/fontawesome-webfont.woff
46.249999664724
https://use.typekit.net/af/9b1c6c/00000000000000000001499c/21/l?subset_id=2&fvd=n7&v=3
30.199999921024
https://use.typekit.net/af/4b77d9/0000000000000000000148a9/21/l?subset_id=2&fvd=i7&v=3
40.673000272363
https://use.typekit.net/af/0e8ca9/0000000000000000000148a6/21/l?subset_id=2&fvd=n6&v=3
31.884000170976
https://use.typekit.net/af/651407/0000000000000000000148a4/21/l?subset_id=2&fvd=n4&v=3
23.132999893278
https://use.typekit.net/af/222d96/0000000000000000000148a5/21/l?subset_id=2&fvd=i4&v=3
19.606000278145
https://use.typekit.net/af/04aaaa/0000000000000000000148a2/21/l?subset_id=2&fvd=n3&v=3
34.428999759257
https://fonts.gstatic.com/s/roboto/v18/KFOmCnqEu92Fr1Mu4mxKKTU1Kg.woff2
3.2680002041161
https://fonts.gstatic.com/s/roboto/v27/KFOmCnqEu92Fr1Mu4mxKKTU1Kg.woff2
4.8859999515116
Reduce the impact of third-party code — Third-party code blocked the main thread for 2,380 ms
It is advised to either limit, remove or delay the loading of redundant third-party code which may be significantly impacting load performance.
Third-Party Transfer Size (Bytes) Main-Thread Blocking Time (Ms)
649905
1988.26
119112
258.3
114267
110.2
38940
16.312
20949
10.22
841143
0
183513
0
113173
0
24616
0
22412
0
19277
0
13305
0
6306
0
1382
0
Some third-party resources can be lazy loaded with a facade — 2 facade alternatives available
Consider replacing third-party embeds with a facade until they are required (use lazy loading).
Product Transfer Size (Bytes) Main-Thread Blocking Time (Ms)
YouTube Embedded Player (Video)
649905
1988.26
Intercom Widget (Customer Success)
119112
258.3
Does not use passive listeners to improve scrolling performance
Improve the page's scroll performance by marking touch and wheel event listeners as 'passive'.
Source
Image elements do not have explicit `width` and `height`
Reduce layout shifts and improve CLS by setting explicit width and height properties on image elements.
URL Failing Elements
https://static.codehs.com/img/homepage/editor.png
img
https://static.codehs.com/img/homepage/badge_collage.png
img
https://static.codehs.com/img/homepage/articles/new_courses_2021.png
img
https://static.codehs.com/img/homepage/pd.png
img
https://static.codehs.com/img/courses/micro_bit.png
img
https://static.codehs.com/img/homepage/articles/tangible_rewards.png
img
https://static.codehs.com/img/courses/cyber_security.png
img
https://static.codehs.com/img/homepage/articles/fashion_retail.png
img
https://static.codehs.com/img/marketing/pro_page/activities.png
img
https://static.codehs.com/img/courses/intro_cs.png
img
https://static.codehs.com/img/marketing/pro_page/fast_grade.png
img
https://static.codehs.com/img/courses/intro_python.png
img
https://static.codehs.com/img/logos/codehs_logo_dark_text.png
https://static.codehs.com/img/brand_logo.png
img
https://static.codehs.com/img/marketing/icons/chevron-left.png
img
https://static.codehs.com/img/marketing/icons/chevron-left.png
img
87

Accessibility

Indicates how accessible the page is and highlights opportunities where the page can be made more accessible to users of codehs.com. This includes details about various page attributes that can be optimized.

Navigation

`[accesskey]` values are unique
Access keys assist users with focusing on different parts of the page. Each access key should be unique for proper navigation.
The page contains a heading, skip link, or landmark region
It is advised to provide ways to bypass repetitive content, allowing users to navigate the page efficiently.
`[id]` attributes on active, focusable elements are unique
Ensure all focusable elements have a unique id value to allow them to be visible to users of assistive technologies, like a screen reader.
Heading elements appear in a sequentially-descending order
Properly order all headers and do not skip heading levels to better the navigation and readability for users of assistive technologies, like a screen reader.
No element has a `[tabindex]` value greater than 0
Although technically valid, a tabindex value greater than 0 often creates frustrating experiences for users who rely on assistive technologies.

ARIA

`[aria-*]` attributes match their roles
Avoid mismatching 'aria-*' attributes and their 'role' value, as it invalidates the attribute.
`button`, `link`, and `menuitem` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
`[aria-hidden="true"]` is not present on the document `<body>`
If aria-hidden=true is set on the document body, assistive technologies, like a screen reader will work inconsistently.
`[aria-hidden="true"]` elements do not contain focusable descendents
Interactive elements within an aria-hidden=true element are unavailable to users of assistive technologies, like a screen reader.
ARIA input fields have accessible names
Generic names are announced to users of assistive technologies, like a screen reader, when an input field does not have an accessible name specified.
ARIA `meter` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
ARIA `progressbar` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
`[role]`s have all required `[aria-*]` attributes
Some ARIA roles have required 'aria-*' attributes, which provide essential information about state and functionality.
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
Some ARIA parent roles cannot perform their intended functions if specific child roles are not used.
`[role]`s are contained by their required parent element
Some ARIA child roles cannot perform their intended functions if specific parent roles are not used.
`[role]` values are valid
All ARIA roles require valid values to perform their intended functions.
ARIA toggle fields have accessible names
Generic names are announced to users of assistive technologies, like a screen reader, when a toggle field does not have an accessible name specified.
ARIA `tooltip` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
ARIA `treeitem` elements have accessible names
Without accessible names on elements, screen readers will default to announcing a generic name, which means your content will be less accessible to users who rely on screen readers.
`[aria-*]` attributes have valid values
ARIA attributes cannot be interpreted with invalid values when used by screen readers and other assistive technologies.
`[aria-*]` attributes are valid and not misspelled
ARIA attributes cannot be interpreted with invalid names when used by screen readers and other assistive technologies.
ARIA IDs are unique
Ensure all ARIA ID values are unique to prevent elements from being overlooked by assistive technologies, like a screen reader.

Names and labels

Buttons have an accessible name
Buttons become unusable as they are announced simply as "button" when the button does not have an accessible name, when used by screen readers and other assistive technologies.
Document has a `<title>` element
Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
No form fields have multiple labels
Having multiple labels for form fields can be confusing to assistive technologies, like a screen reader.
`<frame>` or `<iframe>` elements have a title
Screen reader users and other assistive technology users rely on frame titles to describe the contents of frames.
`<input type="image">` elements have `[alt]` text
Input buttons with alternative text assist screen readers and other assistive technology users to understand its purpose.
Form elements have associated labels
Screen readers and other assistive technologies rely on labels to properly announce form controls.
`<object>` elements have `[alt]` text
It is advised that alt text is used on '<object>' elements in order to provide meaning to screen reader and other assistive technology users, as these technologies are unable to translate non-text content.

Tables and lists

`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Screen readers and other assistive technologies may produce poor and inaccurate output when definition lists are not properly marked up.
Definition list items are wrapped in `<dl>` elements
In order for screen readers and other assistive technologies to properly announce definition list items ('<dt>' and '<dd>'), they must be wrapped in parent a '<dl>' element.
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
Use proper list structure to aid screen readers and other assistive technologies.
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
In order for screen readers to announce list items, ensure that list items ('<li>') are contained within parent '<ul>' or '<ol>' tags.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that '<td>' cells using the headers attribute only refer to other cells in the same table, to improve screen reader user experience.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
Screen readers and other assistive technologies have features to make navigating tables easier. Ensure that table headers refer to some set of cells, to improve screen reader user experience.

Internationalization and localization

`<html>` element has a `[lang]` attribute
It is advised to provide a lang attribute so that screen readers and other assistive technologies are guaranteed to announce the page's text correctly. When not provided, the user's default language setting will be used which may cause inaccuracies.
`<html>` element has a valid value for its `[lang]` attribute
Specify a valid BCP 47 language in order to help screen readers and other assistive technologies announce text properly.
`[lang]` attributes have a valid value
Specify a valid BCP 47 language on elements in order to help screen readers and other assistive technologies announce text properly.

Best practices

The document does not use `<meta http-equiv="refresh">`
Pages that refresh automatically cause a poor user experience as focus is directed back to the top of the page unexpectedly.
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
For users with low vision who rely on screen magnification, ensure that zooming is not disabled.

Audio and video

`<video>` elements contain a `<track>` element with `[kind="captions"]`
Codehs.com may provide assistance to deaf or hearing-impaired users with captions on videos.

Contrast

Names and labels

Image elements do not have `[alt]` attributes
Provide short and descriptive alternative text where possible on informative elements.
Failing Elements
img
img
img
img
img
img
img
img
img
img
img
img
img
img
Links do not have a discernible name
In order to improve the navigation for screen reader and other assistive technology users, use link text that is unique, focusable and discernible.

Manual Checks

The page has a logical tab order
The visual layout should be logical in its tab order and users cannot focus elements that are offscreen.
Interactive controls are keyboard focusable
Ensure that custom interactive controls are keyboard focusable and that a focus indicator is displayed.
Interactive elements indicate their purpose and state
Ensure that interactive elements (such as links and buttons) are distinguishable from non-interactive elements and that they indicate their state.
The user's focus is directed to new content added to the page
When new content (such as a dialogue) is added to the page, the user's focus should be directed to it.
User focus is not accidentally trapped in a region
Avoid focus being accidentally trapped when a user tabs in and out of controls or regions on page.
Custom controls have associated labels
Ensure that custom interactive controls have associated labels, which are provided by aria-label and aria-labelledby attributes.
Custom controls have ARIA roles
Ensure that all custom interactive controls have appropriate ARIA roles.
Visual order on the page follows DOM order
Ensure that the DOM order matches with the page's visual order, in order to improve navigation for screen readers and other assistive technologies.
Offscreen content is hidden from assistive technology
Ensure that offscreen content is hidden through the use of "display:none" styling or the aria-hidden attribute.
HTML5 landmark elements are used to improve navigation
Elements such as <main> and <nav> are recommended as they are used by screen readers and other assistive technologies to improve keyboard navigation.
67

Best Practices

Indicates the recommended, best practices currently in place on the page and highlights the best practices that codehs.com should incorporate. This includes practices such as protecting pages with HTTPS.

Audits

Avoids requesting the geolocation permission on page load
When requesting a user's location, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Avoids requesting the notification permission on page load
When requesting permission to send notifications, provide context or consider tying the request to a user action to avoid confusion and mistrust from users.
Ensure CSP is effective against XSS attacks
Significantly reduce the risk of cross-site scripting attacks (XSS) by ensuring you have a strong Content Security Policy (CSP).
Description Directive Severity
No CSP found in enforcement mode
High

Audits

Allows users to paste into password fields
Ensure that password inputs may be pasted into to aid in the user's ability to use password managers and improve security.
Displays images with correct aspect ratio
Ensure that image display dimensions match their natural aspect ratio.
Serves images with appropriate resolution
For maximum image clarity, ensure images have natural dimensions and are proportional to the display size and pixel ratio.
Fonts with `font-display: optional` are preloaded
It is recommended that optional fonts are preloaded.

Audits

Page has the HTML doctype
Ensure a doctype is specified to prevent the browser from switching to quirks-mode.
Properly defines charset
It is advised to declare a character encoding, optionally via a <meta> tag in the first 1024 bytes of the HTML or in the Content-Type HTTP response header.

Audits

Avoids Application Cache
Application cache is deprecated and is no longer recommended.
Detected JavaScript libraries
Below is a list of all front-end JavaScript libraries that were detected on the page.
Name Version
jQuery
2.2.4
jQuery UI
1.10.1
Lo-Dash
3.10.1
Handlebars
4.7.2
WebFont Loader
Moment.js
2.24.0
Moment Timezone
0.4.1
core-js
core-js-global@3.8.1; core-js-global@3.1.3; core-js-global@3.1.3; core-js-global@3.1.3
Avoids deprecated APIs
Avoid deprecated APIs which will eventually be removed the browser.
No issues in the `Issues` panel in Chrome Devtools
There may be unresolved issues logged to Chrome Devtools.

Audits

Does not use HTTPS — 1 insecure request found
Ensure that all pages are protected with HTTPS (including those that do not handle sensitive data) as HTTPS prevents tampering and passive listening on communications between the app and its users. Additionally, HTTPS is a prerequisite for HTTP/2 and many new web platform APIs.
Insecure URL Request Resolution
http://codehs.com/
Allowed
Includes front-end JavaScript libraries with known security vulnerabilities — 16 vulnerabilities detected
Ensure that the use of third-party scripts is minimal and that only trusted third-party scripts are used as some may contain known security vulnerabilities which may be exploited by attackers.
Library Version Vulnerability Count Highest Severity
4
Medium
1
High
9
High
2
Medium

Audits

Registers an `unload` listener
The 'unload' event does not fire reliably, causing issues with browser optimizations such as the Back-Forward Cache. It is recommended that 'pagehide' or 'visibilitychange' events are used instead.
Source
Browser errors were logged to the console
Below is a list of all errors logged to the console, which indicate unresolved problems on the site.
Source Description
WebSocket connection to 'wss://nexus-websocket-a.intercom.io/pubsub/5-ENrnYVE6HcVSHyHCgJTWjwBQAzeyEnu5eaq1RDz_pMpfQNVEEMqffzZIJ-v5gnUy_K5pYME_sbHM3jtiXcY-6OpKKNYsogRDOf9f?X-Nexus-New-Client=true&X-Nexus-Version=0.8.5&user_role=undefined' failed: Error in connection establishment: net::ERR_NAME_NOT_RESOLVED
Missing source maps for large first-party JavaScript
Consider deploying source maps for added benefits such as the ability to debug while in production.
URL Map URL
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/main.js
https://static.codehs.com/gulp/22d2a550a2b162d9c2f1913cb204262ecc531a16/compressed.js
65

SEO

Indicates how well the page is optimized for ranking in search engines and highlights Search Engine Optimization (SEO) opportunities for codehs.com. This includes optimizations such as providing meta data.

Mobile Friendly

Has a `<meta name="viewport">` tag with `width` or `initial-scale`
It is advised to use a '<meta name="viewport">' tag for the optimization of codehs.com on mobile screens.
Document uses legible font sizes — 100% legible text
Font sizes of 12px or less are too small to most mobile users without user gestures and further action. Aim for more than 60% of page text to use font sizes greater than 12px.
Source Selector % of Page Text Font Size
100.00%
≥ 12px

Content Best Practices

Document has a `<title>` element
Search engines, screen reader users and other assistive technology users rely on the title to provide an overview of the page and to help determine if the page is relevant to their search.
Document has a valid `hreflang`
Search engines can be instructed to list specific versions of a page for a given language or region through the use of hreflang links.
Document has a valid `rel=canonical`
Search engines can be suggested which URL should be shown in search results through the use of canonical links.
Document avoids plugins
The content of plugins cannot be indexed by search engines and many devices either restrict or do not support them.

Crawling and Indexing

Page has successful HTTP status code
Avoid pages with unsuccessful HTTP status codes as they may not be indexed by search engines.
Page isn’t blocked from indexing
Pages that cannot be crawled by search engines cannot be indexed or included in their search results. Ensure that search engines have permission to crawl all pages that should be indexed.
robots.txt is valid
Malformed robots.txt files prevent crawlers from understanding how a site wants to be crawled or indexed, which can be devastating to SEO.

Content Best Practices

Document does not have a meta description
Meta descriptions may be used by search engines when displaying a link to the page and should concisely summarize the page's content.
Links do not have descriptive text — 7 links found
Make use of descriptive link text to assist search engines in understanding the content.
Image elements do not have `[alt]` attributes
Provide short and descriptive alternative text where possible on informative elements.
Failing Elements
img
img
img
img
img
img
img
img
img
img
img
img
img
img

Crawling and Indexing

Links are not crawlable
Ensure that the 'href' attribute of anchor elements links to the appropriate destination. This allows for more pages of the site to be discovered by search engines.

Mobile Friendly

Tap targets are not sized appropriately — 44% appropriately sized tap targets
Interactive elements (such as buttons and links) should be appropriately spaced, sized and easy enough to select or tap with regard to their surrounding elements.
Tap Target Size Overlapping Target
PD
16x15
23x15
23x15
C++
20x15
24x15
28x15
24x15
32x15
32x15
35x15
36x15
38x15
38x15
28x15
C++
20x15
SQL
59x15
42x15
42x15
42x15
42x15
42x15
43x15
42x15
55x15
55x15
65x15
96x15
68x15
56x15
99x15
130x15
113x15
87x15
69x15
116x15
119x15
49x15
49x15
49x15
62x15
52x15
53x15

Manual Checks

Structured data is valid
Structured data can be validated through the use of the Structured Data Testing Tool and the Structured Data Linter.
42

Progressive Web App

Indicates how valid the aspects of a Progressive Web App (PWA) are for the page and highlights opportunities to enable/improve the PWA of codehs.com. This includes details about web app manifests.

PWA Optimized

Redirects HTTP traffic to HTTPS
It is advised to redirect all HTTP traffic to HTTPS, in order to enable secure web features for all users.
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
It is advised to use a '<meta name="viewport">' tag for the optimization of codehs.com on mobile screens.
Provides a valid `apple-touch-icon`
iOS users of Progressive Web Apps will benefit from an apple touch icon, which can be defined with 'apple-touch-icon', which must point to a non-transparent 192px (or 180px) square PNG.

Installable

Web app manifest or service worker do not meet the installability requirements — 1 reason
User engagement may be increased by leveraging the browsers ability to proactively prompt users to add the app to their homescreen.
Failure reason
No manifest was fetched

PWA Optimized

Does not register a service worker that controls page and `start_url`
A service worker is used to provide Progressive Web Apps the use of features such as working offline, the ability for the app to be added to the homescreen as well as push notifications.
Is not configured for a custom splash screen
Themed splash screens ensure a high-quality user experience at launch for app users.
View Data
Does not set a theme color for the address bar.
A theme may be applied to the browser address bar, which ideally can be made to match the site.
View Data
Content is not sized correctly for the viewport
Ensure that the width of the app's content matches the width of the viewport, otherwise the app might not be optimized for mobile screens.
Manifest doesn't have a maskable icon
Maskable icons are great to ensure that images fill the entire shape when installing the app on a device.

Manual Checks

Site works cross-browser
Ensure that the Progressive Web App works correctly across every major browser.
Page transitions don't feel like they block on the network
Users perceive apps with responsive, snappy transitions as higher peforming and ensures a great user experience, even on a slow network.
Each page has a URL
Ensure that all pages are deep linkable via URL. They should also be unique for the purpose of shareability on social media.
Hosting

Server Location

Server IP Address: 13.226.36.123
Continent: North America
Country: United States
United States Flag
Region:
City:
Longitude: -97.822
Latitude: 37.751
Currencies: USD
USN
USS
Languages: English

Web Hosting Provider

Name IP Address
Amazon.com, Inc.
Registration

Domain Registrant

Private Registration: No
Name:
Organization:
Country:
City:
State:
Post Code:
Email:
Phone:
Note: Registration information is derived from various sources and may be inaccurate.

Domain Registrar

Name IP Address
Misk.com, Inc. 50.16.56.216
Security

Visitor Safety

Mature Content: Not Likely
McAfee WebAdvisor Rating: Safe
WOT Rating:
WOT Trustworthiness: 68/100
WOT Child Safety: 89/100
Note: Safety information is not guaranteed.

SSL/TLS Certificate

Issued To: *.codehs.com
Issued By: Amazon
Valid From: 17th February, 2021
Valid To: 18th March, 2022
Subject: CN = *.codehs.com
Hash: a56486e8
Issuer: CN = Amazon
OU = Server CA 1B
O = Amazon
S = US
Version: 2
Serial Number: 19148177409013244353283708712634123587
Serial Number (Hex): 0E67CE0906FD9F2EFDE0B63242A18543
Valid From: 17th February, 2024
Valid To: 18th March, 2024
Signature Algorithm (Short Name): RSA-SHA256
Signature Algorithm (Long Name): sha256WithRSAEncryption
Authority Key Identifier: keyid:59:A4:66:06:52:A0:7B:95:92:3C:A3:94:07:27:96:74:5B:F9:3D:D0
Extended Key Usage: TLS Web Server Authentication, TLS Web Client Authentication
CRL Distribution Points:
Full Name:
URI:http://crl.sca1b.amazontrust.com/sca1b.crl

Certificate Policies: Policy: 2.23.140.1.2.1

Authority Information Access: OCSP - URI:http://ocsp.sca1b.amazontrust.com
CA Issuers - URI:http://crt.sca1b.amazontrust.com/sca1b.crt

SCT List: Signed Certificate Timestamp:
Version : v1 (0x0)
Log ID : 29:79:BE:F0:9E:39:39:21:F0:56:73:9F:63:A5:77:E5:
BE:57:7D:9C:60:0A:F8:F9:4D:5D:26:5C:25:5D:C7:84
Timestamp : Feb 17 04:06:54.313 2021 GMT
Extensions: none
Signature : ecdsa-with-SHA256
30:45:02:20:53:9E:FB:23:DE:ED:DB:78:66:60:B8:AA:
D7:61:04:F6:1D:6C:AF:80:99:83:5D:97:61:51:ED:1A:
C5:78:C4:3B:02:21:00:F4:15:B2:2B:30:F6:17:CD:2E:
1F:6E:45:20:09:5A:A3:04:85:7F:80:9B:4B:35:E4:FC:
40:09:65:21:F4:9D:58
Signed Certificate Timestamp:
Version : v1 (0x0)
Log ID : 22:45:45:07:59:55:24:56:96:3F:A1:2F:F1:F7:6D:86:
E0:23:26:63:AD:C0:4B:7F:5D:C6:83:5C:6E:E2:0F:02
Timestamp : Feb 17 04:06:54.374 2021 GMT
Extensions: none
Signature : ecdsa-with-SHA256
30:45:02:21:00:B8:A9:B7:6C:28:5E:68:DC:C8:6E:A3:
C1:FA:C6:A9:64:42:30:3A:30:CD:1A:E0:04:ED:A1:44:
D9:60:CC:2D:CB:02:20:14:6F:57:91:E1:6E:1C:3B:51:
13:77:88:B6:7C:81:9F:E3:6B:11:07:53:55:64:9C:79:
0A:05:F2:0D:95:00:06
Key Usage: Digital Signature, Key Encipherment
Basic Constraints: CA:FALSE
Subject Alternative Name: DNS:codehs.com
DNS:www.codehs.com
DNS:*.codehs.com
Technical

DNS Lookup

A Records

Host IP Address Class TTL
codehs.com. 13.226.36.123 IN 59
codehs.com. 13.226.36.49 IN 59
codehs.com. 13.226.36.83 IN 59
codehs.com. 13.226.36.9 IN 59

NS Records

Host Nameserver Class TTL
codehs.com. ns-1399.awsdns-46.org. IN 21599
codehs.com. ns-1584.awsdns-06.co.uk. IN 21599
codehs.com. ns-387.awsdns-48.com. IN 21599
codehs.com. ns-720.awsdns-26.net. IN 21599

MX Records

Priority Host Server Class TTL
1 codehs.com. aspmx.l.google.com. IN 299
10 codehs.com. aspmx2.googlemail.com. IN 299
10 codehs.com. aspmx3.googlemail.com. IN 299
5 codehs.com. alt1.aspmx.l.google.com. IN 299
5 codehs.com. alt2.aspmx.l.google.com. IN 299

SOA Records

Domain Name Primary NS Responsible Email TTL
codehs.com. ns-720.awsdns-26.net. awsdns-hostmaster.amazon.com. 899

TXT Records

Host Value Class TTL
codehs.com. v=spf1 IN 59

HTTP Response Headers

HTTP-Code: HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Date: 22nd July, 2021
Server: Apache/2.4.7 (Ubuntu) mod_wsgi/4.7.0 Python/3.5 OpenSSL/1.0.1f
Connection: keep-alive
X-Frame-Options: SAMEORIGIN
Vary: Host,Cookie,Accept-Encoding
X-Cache: Hit from cloudfront
Via: 1.1 78cc4d359edf91a401bf5898aa1dacc7.cloudfront.net (CloudFront)
X-Amz-Cf-Pop: EWR53-C2
X-Amz-Cf-Id: EmeWfTZIh7lIfkq9l_7JT1O3yf-RyKVKFPPK_9N6Lu8J032y6e9ciQ==
Age: 61730

Whois Lookup

Created: 26th March, 2012
Changed: 13th December, 2016
Expires: 26th March, 2027
Registrar: Misk.com, Inc.
Status: clientTransferProhibited
Nameservers: ns-1399.awsdns-46.org
ns-1584.awsdns-06.co.uk
ns-387.awsdns-48.com
ns-720.awsdns-26.net
Owner Organization: CodeHS, Inc.
Owner State: CA
Owner Country: United States
Full Whois: Domain Name: CODEHS.COM
Registrar WHOIS Server: whois.misk.com
Registrar URL: https://www.misk.com
Updated Date: 2016-12-13T14:37:37Z
Creation Date: 2012-03-26T20:47:10Z
Registrar Registration Expiration Date: 2027-03-26T00:00:00Z
Registrar: Misk.com, Inc.
Registrar IANA ID: 401
Registrar Abuse Contact Email: abuse@misk.com
Registrar Abuse Contact Phone: +1.4252304250
Domain Status: clientTransferProhibited https://www.icann.org/epp#clientTransferProhibited
Registrant Organization: CodeHS, Inc.
Registrant State/Province: CA
Registrant Country: United States
Name Server: NS-1399.AWSDNS-46.ORG
Name Server: NS-1584.AWSDNS-06.CO.UK
Name Server: NS-387.AWSDNS-48.COM
Name Server: NS-720.AWSDNS-26.NET
DNSSEC: unsigned
URL of the ICANN WHOIS Data Problem Reporting System: http://wdprs.internic.net/
>>> Last update of WHOIS database: 2021-07-23T12:32:01Z <<<

For more information on Whois status codes, please visit https://icann.org/epp

TERMS OF USE:
The Data in the Misk.com Registrar WHOIS database is provided to you by Misk.com
for information purposes only, and may be used to assist you in obtaining
information about or related to a domain name's registration record.

You agree that you will use this data only for lawful purposes and that, under no
circumstances will you use this data to allow, enable, or otherwise support:
(a) the transmission of unsolicited advertising
and solicitations of any kind, including spam; or
(b) high volume, automated, electronic processes
that collect or compile this data for any purpose.

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Nameservers

Name IP Address
ns-1399.awsdns-46.org 205.251.197.119
ns-1584.awsdns-06.co.uk 205.251.198.48
ns-387.awsdns-48.com 205.251.193.131
ns-720.awsdns-26.net 205.251.194.208
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