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Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

30

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...900.0 s177.0 KiB
cdn.optimizely.com/js/8171642667.js120.0 s134.7 KiB
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...21600.0 s181.1 KiB
/tags/js/v2/eu1-785e164941c9ed4880842cc0c6d6bf0c/mparticl...3600.0 s58.3 KiB
static.channel4.com/all4-dtm/latest/dtm.js900.0 s46.5 KiB
www.channel4.com/staticfonts/latest/c4.text/punctuation.woff3600.0 s32.4 KiB
www.channel4.com/staticfonts/latest/c4.headline/punctuation.woff3600.0 s28.9 KiB
www.channel4.com/staticfonts/latest/4text.medium/punctuation.woff3600.0 s22.4 KiB
www.channel4.com/staticfonts/latest/4text.medium/lowercase.woff3600.0 s22.4 KiB
www.channel4.com/staticfonts/latest/4text.regular/punctuation.woff3600.0 s22.1 KiB
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...900.0 s13.2 KiB
www.channel4.com/consent/loader.js?mountpoint=cookie-consent-banner872.0 s11.3 KiB
s.go-mpulse.net/boomerang/XF74S-NBRPP-BVVGB-BSCMM-3V6RK604800.0 s56.1 KiB
static.c4assets.com/all4-ad-code/latest/adverts.js900.0 s6.0 KiB
mssl.fwmrm.net/p/c4_display/LinkTag2.js?0.0 ms2.7 KiB
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...900.0 s2.1 KiB
/maze-universal-loader.js?apiKey=4f48c7e5-f420-4f3d-8fcf-...43200.0 s2.7 KiB
/all4-dtm/latest/b8b3c372794b/RC1ccad7261ae1404ba561eefcb...900.0 s1.1 KiB
/all4-dtm/latest/b8b3c372794b/RC4eee81b06a674aa790a559fd9...900.0 s1016 B
/all4-dtm/latest/b8b3c372794b/RC20d7ca4abe3547efb0eeb64d7...900.0 s998 B
/all4-dtm/latest/b8b3c372794b/RC0215f20884cf4ddcabe4edd10...900.0 s877 B
//stylesheet?c4.text&c4.headline&c4.medium&4text.regular&...2297.0 s835 B
/stylesheet?4text.regular&4text.medium&4headline.extrabol...1011.0 s692 B
cdn-pci.optimizely.com/js/geo4.js0.0 ms512 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:66.868 source:map[column:824689 line:2 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:0.496 source:map[column:362557 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:28.936 source:map[column:636100 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:14.281 source:map[column:1.165333e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:8.242 source:map[column:1.160058e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:14.913 source:map[column:1.276285e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:0.743 source:map[column:1.407828e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]] map[reflowTime:20.189 source:map[column:1.096946e+06 line:1 type:source-location url:https://www.channel4.com/homepage/static/2.1.47/js/homepage.js urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
https://ic.c4assets.com/bips/collections/308ECADF-32C0-4cdd-816d-0cf472a03761.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/308ECADF-32C0-4cdd-816d-0cf472a03761.jp...143.4 KiB135.9 KiB
https://ic.c4assets.com/bips/collections/7BACA07E-A75A-4488-af69-6793f8aaf513.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7BACA07E-A75A-4488-af69-6793f8aaf513.jp...131.1 KiB123.6 KiB
https://ic.c4assets.com/bips/collections/A6E7BB13-7B0F-416c-ad98-d641798270fd.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A6E7BB13-7B0F-416c-ad98-d641798270fd.jp...124.4 KiB116.9 KiB
https://ic.c4assets.com/bips/collections/A6E7BB13-7B0F-4ace-aa88-91008c1aceb2.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A6E7BB13-7B0F-4ace-aa88-91008c1aceb2.jp...124.4 KiB116.9 KiB
https://ic.c4assets.com/bips/collections/CFEAF986-1843-4959-824a-c537cc115f2f.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/CFEAF986-1843-4959-824a-c537cc115f2f.jp...120.6 KiB113.1 KiB
https://ic.c4assets.com/bips/collections/0692B70D-66BA-403c-884b-f42195cc5649.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/0692B70D-66BA-403c-884b-f42195cc5649.jp...117.8 KiB110.3 KiB
https://ic.c4assets.com/bips/collections/CFA6B2CC-7233-4148-9e88-9bc888a62777.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/CFA6B2CC-7233-4148-9e88-9bc888a62777.jp...102.3 KiB94.8 KiB
https://ic.c4assets.com/bips/collections/2cf39f60-b5b4-4eec-834c-6b592f9cb614.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/2cf39f60-b5b4-4eec-834c-6b592f9cb614.jp...98.1 KiB90.6 KiB
https://ic.c4assets.com/bips/collections/8014C3A9-6A72-489f-9992-1f2d503b30e0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/8014C3A9-6A72-489f-9992-1f2d503b30e0.jp...96.8 KiB89.3 KiB
https://ic.c4assets.com/bips/collections/32E9F07C-BFDD-4380-8000-07223b5373d9.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/32E9F07C-BFDD-4380-8000-07223b5373d9.jp...96.4 KiB88.9 KiB
https://ic.c4assets.com/bips/collections/08BAC8A6-DE84-403f-b94d-243727fd16bf.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/08BAC8A6-DE84-403f-b94d-243727fd16bf.jp...95.2 KiB87.7 KiB
https://ic.c4assets.com/bips/collections/7C769E31-1996-483e-9781-6ea1795863c7.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7C769E31-1996-483e-9781-6ea1795863c7.jp...94.6 KiB87.1 KiB
https://ic.c4assets.com/bips/collections/8F146414-0E74-4177-bde6-e6f6b7f6e57b.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/8F146414-0E74-4177-bde6-e6f6b7f6e57b.jp...93.4 KiB85.8 KiB
https://ic.c4assets.com/bips/collections/56F915BF-77E4-4ad3-acdf-dbfe28356fd0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/56F915BF-77E4-4ad3-acdf-dbfe28356fd0.jp...92.9 KiB85.4 KiB
https://ic.c4assets.com/bips/collections/C5D6E1B5-6B7E-46e1-be7e-40fd09c1ac2a.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/C5D6E1B5-6B7E-46e1-be7e-40fd09c1ac2a.jp...91.0 KiB83.5 KiB
https://ic.c4assets.com/bips/collections/32CC21ED-B55A-4eda-acbf-ef903df200ad.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/32CC21ED-B55A-4eda-acbf-ef903df200ad.jp...90.9 KiB83.3 KiB
https://ic.c4assets.com/bips/collections/B8E9F339-E08F-41be-a1f1-bcd555c33574.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/B8E9F339-E08F-41be-a1f1-bcd555c33574.jp...90.6 KiB83.1 KiB
https://ic.c4assets.com/bips/collections/A9EE1689-E2A4-4c6a-884a-ebba0f52c598.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A9EE1689-E2A4-4c6a-884a-ebba0f52c598.jp...88.6 KiB81.1 KiB
https://ic.c4assets.com/bips/collections/290C7E87-BD16-4b2e-be51-7e3639eab3ae.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/290C7E87-BD16-4b2e-be51-7e3639eab3ae.jp...87.7 KiB80.1 KiB
https://ic.c4assets.com/bips/collections/35EBF852-EE30-4c78-a7ee-2b680dd9d419.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/35EBF852-EE30-4c78-a7ee-2b680dd9d419.jp...86.8 KiB79.3 KiB
https://ic.c4assets.com/bips/collections/A4E55A49-6D91-43fb-9330-dfcbd90c6849.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/A4E55A49-6D91-43fb-9330-dfcbd90c6849.jp...82.8 KiB75.3 KiB
https://ic.c4assets.com/bips/collections/F57743AC-A9E3-4610-84e4-179ac57fb298.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/F57743AC-A9E3-4610-84e4-179ac57fb298.jp...82.3 KiB74.8 KiB
https://ic.c4assets.com/bips/collections/DE1CE5C4-FE03-4c24-8719-f8d0972967c0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/DE1CE5C4-FE03-4c24-8719-f8d0972967c0.jp...80.2 KiB72.7 KiB
https://ic.c4assets.com/bips/collections/8342F184-425C-4a5e-8a9f-5e7e584c9386.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/8342F184-425C-4a5e-8a9f-5e7e584c9386.jp...80.1 KiB72.5 KiB
https://ic.c4assets.com/bips/collections/F425EE7C-1112-44c7-aadd-4dedcbcd10f7.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/F425EE7C-1112-44c7-aadd-4dedcbcd10f7.jp...79.6 KiB72.1 KiB
https://ic.c4assets.com/bips/collections/387793B0-9B13-4ed2-b7cb-5019d9d31df8.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/387793B0-9B13-4ed2-b7cb-5019d9d31df8.jp...79.4 KiB71.9 KiB
https://ic.c4assets.com/bips/collections/387793B0-9B13-4f76-9039-211cec26f1dc.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/387793B0-9B13-4f76-9039-211cec26f1dc.jp...79.4 KiB71.9 KiB
https://ic.c4assets.com/bips/collections/43bca549-afe5-47f0-addd-c4998352b095.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/43bca549-afe5-47f0-addd-c4998352b095.jp...78.5 KiB71.0 KiB
https://ic.c4assets.com/bips/collections/723348F2-C6A7-4696-851a-7b4cf2cbab4a.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/723348F2-C6A7-4696-851a-7b4cf2cbab4a.jp...78.5 KiB71.0 KiB
https://ic.c4assets.com/bips/collections/0497BDC0-EC0A-4902-b11f-1b82e76d726b.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/0497BDC0-EC0A-4902-b11f-1b82e76d726b.jp...78.3 KiB70.8 KiB
https://ic.c4assets.com/bips/collections/423E11FA-DD2D-4913-94c9-adc4d821a64d.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/B661E3B6-7A74-4510-a208-66b57f4e4594.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/3277395F-6FD7-474f-b1ca-9f2846637791.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/78465688-B622-4515-b882-9b172d9aac2b.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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/bips/collections/F2D5C420-83D3-4084-9b2e-22e102ce8f73.jp...72.4 KiB64.9 KiB
https://ic.c4assets.com/bips/collections/CECDCF6D-F668-4b4f-90ee-416f7bfac35e.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/CECDCF6D-F668-4b4f-90ee-416f7bfac35e.jp...70.7 KiB63.1 KiB
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/bips/collections/B967A0C8-41B3-4378-9e69-2162b71ca321.jp...70.5 KiB62.9 KiB
https://ic.c4assets.com/bips/collections/9E054421-DD3C-440f-9804-9b4fabad3592.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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https://ic.c4assets.com/bips/collections/60AFF2DA-B5F1-44d4-a7cd-32fe083f78de.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
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/bips/collections/BB50F38F-7BDA-471f-8432-f1fdf6783c53.jp...59.5 KiB51.9 KiB
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https://ic.c4assets.com/bips/collections/17D6DFC0-C203-4d94-a9b7-518582febcf1.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/17D6DFC0-C203-4d94-a9b7-518582febcf1.jp...57.5 KiB50.0 KiB
https://ic.c4assets.com/bips/collections/95DFC157-AA4F-4699-be6c-1966e94448be.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/95DFC157-AA4F-4699-be6c-1966e94448be.jp...57.1 KiB49.6 KiB
https://ic.c4assets.com/bips/collections/4B18528B-EC63-4743-9280-266aeda73791.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/4B18528B-EC63-4743-9280-266aeda73791.jp...56.6 KiB49.0 KiB
https://ic.c4assets.com/bips/collections/E3F30F51-1978-4520-b00a-a3a6a7055970.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/E3F30F51-1978-4520-b00a-a3a6a7055970.jp...56.5 KiB49.0 KiB
https://ic.c4assets.com/bips/collections/c77e6ce9-f0d9-4f2a-8d98-b29b11d680c8.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/c77e6ce9-f0d9-4f2a-8d98-b29b11d680c8.jp...56.4 KiB48.9 KiB
div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.jpg?imf...56.2 KiB46.7 KiB
https://ic.c4assets.com/bips/collections/AB0F5301-C46E-4f9f-a638-b696951e11a6.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/AB0F5301-C46E-4f9f-a638-b696951e11a6.jp...52.4 KiB45.3 KiB
https://ic.c4assets.com/bips/collections/636E1505-8206-48e0-9388-4e2582576733.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/636E1505-8206-48e0-9388-4e2582576733.jp...51.0 KiB44.1 KiB
https://ic.c4assets.com/bips/collections/7D6A57DF-C8D9-4593-9456-9a8d2cecf204.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7D6A57DF-C8D9-4593-9456-9a8d2cecf204.jp...49.8 KiB43.0 KiB
https://ic.c4assets.com/bips/collections/388B966E-5AD4-4ed9-9948-0c0c05d918e7.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/388B966E-5AD4-4ed9-9948-0c0c05d918e7.jp...49.6 KiB42.9 KiB
https://ic.c4assets.com/bips/collections/655436D6-7A4E-43bb-9458-13be94e539d1.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/655436D6-7A4E-43bb-9458-13be94e539d1.jp...49.6 KiB42.9 KiB
https://ic.c4assets.com/bips/collections/3298CAAC-2922-407e-89c7-62361c5cb9be.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/3298CAAC-2922-407e-89c7-62361c5cb9be.jp...49.4 KiB42.7 KiB
https://ic.c4assets.com/bips/collections/C5D5D620-C4EE-41ed-bc85-cd1c82cc9e99.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/C5D5D620-C4EE-41ed-bc85-cd1c82cc9e99.jp...47.4 KiB41.0 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/1A0581A2-35BB-47ef-80da-f28eae25d0e9.jp...43.9 KiB40.2 KiB
https://ic.c4assets.com/bips/collections/C4097ABE-D02F-449d-86a9-29ffe7973c69.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/C4097ABE-D02F-449d-86a9-29ffe7973c69.jp...45.9 KiB39.7 KiB
https://ic.c4assets.com/bips/collections/2D14DDE8-20B2-4e80-b6d6-2c0dadcbe975.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/2D14DDE8-20B2-4e80-b6d6-2c0dadcbe975.jp...45.5 KiB39.3 KiB
https://ic.c4assets.com/bips/collections/7E9B4975-9D24-4251-b21b-ea8baba4a47b.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7E9B4975-9D24-4251-b21b-ea8baba4a47b.jp...45.3 KiB39.1 KiB
https://ic.c4assets.com/bips/collections/ae66ff38-6476-447e-b788-41cd8beb0604.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/ae66ff38-6476-447e-b788-41cd8beb0604.jp...43.3 KiB37.4 KiB
https://ic.c4assets.com/bips/collections/DC649EF1-68DE-4ce8-b3f4-3fd36ca89ba8.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/DC649EF1-68DE-4ce8-b3f4-3fd36ca89ba8.jp...42.5 KiB36.7 KiB
https://ic.c4assets.com/bips/collections/EB5D8ABF-1D0B-48cf-b32c-c67b3cdc0018.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/EB5D8ABF-1D0B-48cf-b32c-c67b3cdc0018.jp...36.9 KiB31.9 KiB
https://ic.c4assets.com/bips/collections/8AC1592D-05EE-4588-887f-788c8d906a2a.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/8AC1592D-05EE-4588-887f-788c8d906a2a.jp...36.3 KiB31.4 KiB
https://ic.c4assets.com/bips/collections/4C51C13E-F5D6-486d-9aad-43aee3935f83.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/4C51C13E-F5D6-486d-9aad-43aee3935f83.jp...35.2 KiB30.4 KiB
https://ic.c4assets.com/bips/collections/F84D84C5-1A6C-42be-abc4-7de72bd603a0.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/F84D84C5-1A6C-42be-abc4-7de72bd603a0.jp...34.2 KiB29.6 KiB
Your Song div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper > div.all4-superhero-slice__hero-content > img.all4-superhero-slice__hero__title
/bips/159381/44CD9E43-00D4-4308-92c0-12b162690b7f.png?imf...30.2 KiB29.5 KiB
https://ic.c4assets.com/bips/collections/C92D6B29-8AE6-46c9-84fd-b7d200f33027.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/C92D6B29-8AE6-46c9-84fd-b7d200f33027.jp...32.3 KiB28.0 KiB
https://ic.c4assets.com/bips/collections/FAFE6B76-D9D9-4c67-be98-37e5a298b28d.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/FAFE6B76-D9D9-4c67-be98-37e5a298b28d.jp...30.1 KiB26.0 KiB
https://ic.c4assets.com/bips/collections/16BD9042-7385-4462-99c4-b567664263b2.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/16BD9042-7385-4462-99c4-b567664263b2.jp...29.7 KiB25.6 KiB
https://ic.c4assets.com/bips/collections/2EBF9BD1-B15F-4a9b-bf2f-d6b0bd79896d.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/2EBF9BD1-B15F-4a9b-bf2f-d6b0bd79896d.jp...29.5 KiB25.5 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/B577486A-7450-47e3-b61e-8e847d65aeeb.jp...29.2 KiB25.4 KiB
https://ic.c4assets.com/bips/collections/D2480F39-AE8C-46e2-88eb-4cdafecc03d6.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/D2480F39-AE8C-46e2-88eb-4cdafecc03d6.jp...27.0 KiB23.3 KiB
https://ic.c4assets.com/bips/collections/7C99647D-9206-4abf-a0a7-1fb2fe2b66ab.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/7C99647D-9206-4abf-a0a7-1fb2fe2b66ab.jp...26.9 KiB23.3 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/08580D8B-3BCE-4eb2-ab99-15b41b831b7d.jp...25.6 KiB21.9 KiB
https://ic.c4assets.com/bips/collections/3F707659-A8D2-4c5c-a479-9502ae32a3c5.j… div.block__image-border-wrapper > div.block__image-wrapper > div.block__image-container > img.swiper-lazy
/bips/collections/3F707659-A8D2-4c5c-a479-9502ae32a3c5.jp...22.6 KiB19.6 KiB
h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image h3 > div.all4-slice-item__content-area > div.all4-slice-item__image-mask > img.all4-slice-item__image
/bips/collections/C410205C-42E1-41fd-bb48-74b58861bb33.jp...20.2 KiB16.9 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]
items: [map[duration:382.188 label:Time to first byte subpart:timeToFirstByte] map[duration:1651.234 label:Resource load delay subpart:resourceLoadDelay] map[duration:60.754 label:Resource load duration subpart:resourceLoadDuration] map[duration:585.593 label:Element render delay subpart:elementRenderDelay]]
lhId: page-54-IMG
nodeLabel: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
path: 1,HTML,1,BODY,5,DIV,2,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,SECTION,0,IMG
selector: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
snippet: <img alt="" src="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" srcset="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" sizes="(min-width: 3840px) 100vw, (min-width: 2160px) 100vw, (min-width: 1920px) …" loading="eager">

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-54-IMG
nodeLabel: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
path: 1,HTML,1,BODY,5,DIV,2,DIV,1,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,SECTION,0,IMG
selector: div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
snippet: <img alt="" src="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" srcset="https://ic.c4assets.com/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.j…" sizes="(min-width: 3840px) 100vw, (min-width: 2160px) 100vw, (min-width: 1920px) …" loading="eager">

HTTP/2 and HTTP/3 offer many benefits over HTTP/1.1, such as multiplexing. Learn more about using modern HTTP.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLProtocol
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...http/1.1
static.c4assets.com/all4-ad-code/latest/adverts.jshttp/1.1
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...http/1.1
/all4-dtm/latest/b8b3c372794b/hostedLibFiles/EP8757b50353...http/1.1
all4nav.channel4.com/globalnav/static/2.1.34/css/style.csshttp/1.1
all4nav.channel4.com/globalnav/static/2.1.34/4e315d50e1681ec6c8b1.svghttp/1.1
all4nav.channel4.com/globalnav/static/2.1.34/fonts/fouricons_v2_3..woffhttp/1.1
all4nav.channel4.com/v1/api/versions?browserName=CHROMEhttp/1.1
all4nav.channel4.com/globalnav/static/2.1.34/images/all4_logo.svghttp/1.1
all4nav.channel4.com/globalnav/static/2.1.34/images/arrow.svghttp/1.1
all4nav.channel4.com/globalnav/static/2.1.34/images/account_icon.svghttp/1.1
all4nav.channel4.com/globalnav/static/2.1.34/images/search_icon.svghttp/1.1
/all4-dtm/latest/b8b3c372794b/RC20d7ca4abe3547efb0eeb64d7...http/1.1
all4nav.channel4.com/globalnav/static/2.1.34/images/all4plus_logo.svghttp/1.1
/all4-dtm/latest/b8b3c372794b/RC4eee81b06a674aa790a559fd9...http/1.1
/all4-dtm/latest/b8b3c372794b/RC0215f20884cf4ddcabe4edd10...http/1.1
/all4-dtm/latest/b8b3c372794b/RC1ccad7261ae1404ba561eefcb...http/1.1

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.
description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
www.channel4.com/homepage/static/2.1.47/js/homepage.js304.2 KiB3.9 s
cdn.optimizely.com/js/8171642667.js134.7 KiB2.8 s
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...181.1 KiB1.1 s

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLEst Savings
all4nav.channel4.com/globalnav/static/2.1.34/fonts/fouricons_v2_3..woff5.0 ms

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 991 ms
URLTime Spent
channel4.com/991 ms
www.channel4.com/0.0 ms

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 20.0 KiB
URLTransfer SizeEst Savings
cdn.optimizely.com/js/8171642667.js134.1 KiB20.0 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 600 ms 65.8 KiB
URLTransfer SizeEst Savings
www.channel4.com/homepage/static/2.1.47/css/style.css46.3 KiB43.9 KiB
all4nav.channel4.com/globalnav/static/2.1.34/css/style.css22.5 KiB21.9 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 2.3 s 381.9 KiB
URLTransfer SizeEst Savings
www.channel4.com/homepage/static/2.1.47/js/homepage.js303.5 KiB156.0 KiB
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...176.5 KiB69.9 KiB
cdn.optimizely.com/js/8171642667.js134.1 KiB53.3 KiB
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...180.0 KiB37.2 KiB
s.go-mpulse.net/boomerang/XF74S-NBRPP-BVVGB-BSCMM-3V6RK55.9 KiB36.4 KiB
/tags/js/v2/eu1-785e164941c9ed4880842cc0c6d6bf0c/mparticl...57.9 KiB29.1 KiB

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTotal CPU TimeScript EvaluationScript Parse
www.channel4.com/homepage/static/2.1.47/js/homepage.js3.5 s2.5 s183 ms
cdn.optimizely.com/js/8171642667.js1.2 s674 ms71 ms
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...1.0 s871 ms76 ms
Unattributable997 ms162 ms0.0 ms
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...728 ms515 ms79 ms
s.go-mpulse.net/boomerang/XF74S-NBRPP-BVVGB-BSCMM-3V6RK295 ms61 ms30 ms
www.channel4.com/278 ms37 ms5.4 ms
static.channel4.com/all4-dtm/latest/dtm.js169 ms136 ms23 ms
www.channel4.com/consent/static/2.1.20/renderer.f21543f785a782a39cdc.js162 ms130 ms13 ms
/tags/js/v2/eu1-785e164941c9ed4880842cc0c6d6bf0c/mparticl...142 ms111 ms29 ms
static.c4assets.com/all4-ad-code/latest/adverts.js109 ms91 ms2.3 ms
www.channel4.com/consent/static/2.1.20/359.a606b1e83717ef7d245c.js90 ms53 ms15 ms
www.channel4.com/consent/static/2.1.20/435.7c0718c6760cb204ac89.js89 ms55 ms18 ms
cdn-pci.optimizely.com/js/geo4.js53 ms52 ms0.3 ms
www.channel4.com/consent/loader.js?mountpoint=cookie-consent-banner51 ms44 ms4.1 ms

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation5.6 s
Other1.5 s
Style & Layout859 ms
Script Parsing & Compilation568 ms
Garbage Collection254 ms
Rendering231 ms
Parse HTML & CSS67 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
The page has an unload handler in a sub frame.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
www.channel4.com/homepage/static/2.1.47/js/homepage.js304.2 KiB
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...181.1 KiB
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...177.0 KiB
www.channel4.com/api/homepage?158.4 KiB
/bips/collections/308ECADF-32C0-4cdd-816d-0cf472a03761.jp...143.7 KiB
cdn.optimizely.com/js/8171642667.js134.7 KiB
/bips/collections/7BACA07E-A75A-4488-af69-6793f8aaf513.jp...131.4 KiB
/bips/collections/A6E7BB13-7B0F-416c-ad98-d641798270fd.jp...124.7 KiB
/bips/collections/A6E7BB13-7B0F-4ace-aa88-91008c1aceb2.jp...124.7 KiB
/bips/collections/CFEAF986-1843-4959-824a-c537cc115f2f.jp...120.8 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
Your Song div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper > div.all4-superhero-slice__hero-content > img.all4-superhero-slice__hero__title
/bips/159381/44CD9E43-00D4-4308-92c0-12b162690b7f.png?imf...
div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img div > div.all4-superhero-slice > section.all4-superhero-slice__image-pane > img
/bips/159381/23964E91-3A84-4804-b622-fbdf954b19f1.jpg?imf...
Channel4.com Homepage li.nav__list__item > a#all4-logo > div.nav__list__item__link__content > img.all4gn__home-image
all4nav.channel4.com/globalnav/static/2.1.34/images/all4_logo.svg
Sign in li.nav__list__item > a.nav__list__item__link > div.nav__list__item__link__content > img.signIn-icon
all4nav.channel4.com/globalnav/static/2.1.34/images/account_icon.svg
Search li.nav__list__item > a.nav__list__item__link > div.nav__list__item__link__content > img.search-icon
all4nav.channel4.com/globalnav/static/2.1.34/images/search_icon.svg

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits
●Optimize DOM size
●Optimize viewport for mobile
●Minify CSS
●User Timing marks and measures 2 user timings
●Avoid long main-thread tasks 20 long tasks found
●Network Requests
●Network Round Trip Times 80 ms
●Server Backend Latencies 520 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 110 ms
●Avoid large layout shifts 2 layout shifts found
○INP breakdown
○Avoid non-composited animations
96

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

ARIA

ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. Learn how to make ARIA dialog elements more accessible.

Why this matters

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Failing Elements
Your privacy on Channel 4 We use cookies on your device to help us provide a mo… body.touch > div#cookie-consent-banner > div
Your privacy on Channel 4 We use cookies on your device to help us provide a mo… body.touch > div#cookie-consent-banner > div > div.cookie-banner

These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Accept & Continue div.all4-cc-grid > div.all4-cc-popup__content-area > div.all4-cc-grid > button.all4-cc-primary-button
Reject & Continue div.all4-cc-grid > div.all4-cc-popup__content-area > div.all4-cc-grid > button.all4-cc-secondary-button
Ordinary people perform the song that tells their extraordinary story div > div.all4-superhero-slice > div.all4-superhero-slice__overlay-container > div.all4-superhero-slice__wrapper
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Made in Chelsea Reality series following the lives, loves and awks of SW3's br… div.swiper-slide > div.block > div.block__content > a.block__link
The Copenhagen Test Spy thriller. Intelligence analyst Alexander Hale realises… div.swiper-slide > div.block > div.block__content > a.block__link
Suez: 24 Hours That… The dramatic inside story of the Suez Crisis, which chang… div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
The drama starts here The biggest and best dramas from the UK, the US and beyo… div.swiper-slide > div.block > div.block__content > a.block__link
A Woman of Substance Epic rags-to-riches saga of Emma Harte’s rise from housem… div.swiper-slide > div.block > div.block__content > a.block__link
It's A Sin Drama from Russell T Davies about five friends living and loving in… div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Click here for Comedy All-you-can-eat comedy! Get stuck in. div.swiper-slide > div.block > div.block__content > a.block__link
The Inbetweeners Smash-hit adolescent comedy about a bunch of lads behaving sa… div.swiper-slide > div.block > div.block__content > a.block__link
Big Mood Maggie's bipolar disorder puts her friendship with bestie Eddie to th… div.swiper-slide > div.block > div.block__content > a.block__link
View all (20) section.slice > div.slice__header > div.slice__header--wrapper > a.all4-collection-cta
Find a new favourite Great films you know, great films you don't div.swiper-slide > div.block > div.block__content > a.block__link
Plane (2023) Action with Gerard Butler. A pilot crash-lands on an island full … div.swiper-slide > div.block > div.block__content > a.block__link
Sonic the Hedgehog (2020) Madcap adventure-comedy adaptation of the iconic vid… div.swiper-slide > div.block > div.block__content > a.block__link
○Interactive controls are keyboard focusable
○Interactive elements indicate their purpose and state
○The page has a logical tab order
○Visual order on the page follows DOM order
○User focus is not accidentally trapped in a region
○The user's focus is directed to new content added to the page
○HTML5 landmark elements are used to improve navigation
○Offscreen content is hidden from assistive technology
○Custom controls have associated labels
○Custom controls have ARIA roles
●`[aria-*]` attributes match their roles
●`[aria-hidden="true"]` is not present on the document `<body>`
●`[role]`s have all required `[aria-*]` attributes
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●Buttons have an accessible name
●Image elements have `[alt]` attributes
●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
●`button`, `link`, and `menuitem` elements have accessible names
●ARIA attributes are used as specified for the element's role
●`[aria-hidden="true"]` elements do not contain focusable descendents
●Elements use only permitted ARIA attributes
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links have a discernible name
●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
●No element has a `[tabindex]` value greater than 0
●Touch targets have sufficient size and spacing.
●Heading elements appear in a sequentially-descending order
●Document has a main landmark.
●Deprecated ARIA roles were not used
●Identical links have the same purpose.
○`[accesskey]` values are unique
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
○`[role]`s are contained by their required parent element
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○The page contains a heading, skip link, or landmark region
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<frame>` or `<iframe>` elements have a title
○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
○Input buttons have discernible text.
○`<input type="image">` elements have `[alt]` text
○Form elements have associated labels
○Links are distinguishable without relying on color.
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
○`[lang]` attributes have a valid value
○`<video>` elements contain a `<track>` element with `[kind="captions"]`
○Tables have different content in the summary attribute and `<caption>`.
○All heading elements contain content.
○Uses ARIA roles only on compatible elements
○Image elements do not have `[alt]` attributes that are redundant text.
○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
○`<td>` elements in a large `<table>` have one or more table headers.
77

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
Unload event listeners are deprecated and will be removed.
s.go-mpulse.net/boomerang/XF74S-NBRPP-BVVGB-BSCMM-3V6RK line 9, col 11504

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

Why this matters

Performance issues directly impact user engagement and conversion rates.

SourceDescription
/id?d_visid_ver=5.5.0&d_fieldgroup=A&mcorgid=16B222CE5278...
Failed to load resource: net::ERR_CERT_COMMON_NAME_INVALID

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
www.channel4.com/homepage/static/2.1.47/js/homepage.js
/hEtR9X5wZ/joG_KTcx/ru42TWYm/I0/5Y1iDpfc4tJzkf9c/H0YtIFFv...
/v1/js/loader.js?fullNav=yes&header=header&footer=footer&...
●Uses HTTPS
●Avoids third-party cookies
●Allows users to paste into input fields
●Avoids requesting the geolocation permission on page load
●Avoids requesting the notification permission on page load
●Displays images with correct aspect ratio
●Serves images with appropriate resolution
●Page has the HTML doctype
●Properly defines charset
●No issues in the `Issues` panel in Chrome Devtools
●Ensure CSP is effective against XSS attacks
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate DOM-based XSS with Trusted Types
●Detected JavaScript libraries
○Redirects HTTP traffic to HTTPS
○Mitigate clickjacking with XFO or CSP
100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

○Structured data is valid
●Page isn’t blocked from indexing
●Document has a `<title>` element
●Document has a meta description
●Page has successful HTTP status code
●Links have descriptive text
●Links are crawlable
●robots.txt is valid
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`

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