RESOLVED FIXED264864
Use scrollMargin for lazy load intersection observer 
https://bugs.webkit.org/show_bug.cgi?id=264864
Summary Use scrollMargin for lazy load intersection observer
Traian Captan
Reported 2023-11-14 22:43:53 PST
Currently the lazy load intersection observer is set up using a rootMargin. This does not work well for pages that use images in CSS scrollers, like carousels, causing the images to load too late, when they become visible and the intersection with the root is detected. To work around this issue some developers are choosing to not use lazy loading, thus increasing the overall bandwidth usage for their sites. This problem was discussed in issue 431(https://github.com/w3c/IntersectionObserver/issues/431). Using scrollMargin for the lazy load intersection observer will allow lazy loading images to load when they are near the viewport as expected.
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Radar WebKit Bug Importer
Comment 1 2023-11-21 22:44:14 PST
<rdar://problem/118706766>
Simon Fraser (smfr)
Comment 2 2025-03-06 13:09:04 PST
*** This bug has been marked as a duplicate of bug 263370 ***
Johannes Odland
Comment 3 2025-03-08 05:53:22 PST
@smfr This bug is not quite the same as 263370, as this bug relates to using scrollMargin for lazy loading. I'm planning to file a separate PR for this once/if https://github.com/WebKit/WebKit/pull/40687 lands.
Simon Fraser (smfr)
Comment 4 2025-03-10 09:52:50 PDT
Mistaken duplication.
Johannes Odland
Comment 5 2025-04-06 04:29:04 PDT
Pull request: https://github.com/WebKit/WebKit/pull/43712
EWS
Comment 6 2025-04-10 17:20:40 PDT
Committed 293552@main (19ed0f7d93d1): <https://commits.webkit.org/293552@main> Reviewed commits have been landed. Closing PR #43712 and removing active labels.
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