Last modified: 2013-02-10 09:10:17 UTC

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Bug 27418 - CSS Reflows degrading page load performance
CSS Reflows degrading page load performance
Product: MediaWiki
Classification: Unclassified
Interface (Other open bugs)
All All
: Normal major with 1 vote (vote)
: ---
Assigned To: Nobody - You can work on this!
Depends on:
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Reported: 2011-02-14 23:14 UTC by Rob Lanphier
Modified: 2013-02-10 09:10 UTC (History)
5 users (show)

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Description Rob Lanphier 2011-02-14 23:14:39 UTC
The order in which we're loading CSS and Javascript is causing some rather unsightly reflows on more complicated pages (e.g. diff pages, recent changes, page editing).  Even though the CSS and Javascript is being delivered to the browser faster using Resource Loader, this delivery speed benefit is more than offset by the performance penalties of the reflows.

From Roan: "This is because we're loading the styles for these after the page load, even though the elements are present in the page itself. Obviously this is bad: loading styles after page load is only acceptable for things that get inserted by JS (which happens after the styles are loaded). Flashes of unstyled content should not happen."

This is a work item to find and fix areas where we're loading CSS dynamically where we don't need to, and switch to static loading in those cases
Comment 1 Bawolff (Brian Wolff) 2011-02-14 23:20:53 UTC
/me was just going to file a similar bug based on comments floating around at wikinews about diff pages being weird.

>This is a work item to find and fix areas where we're loading CSS dynamically
>where we don't need to, and switch to static loading in those cases

diff pages would be one of them.

People at wikinews also complained that loading css in this manner significantly degrades the user experience for people who have css on, but JS disabled. ( (permalink: )
Comment 2 Trevor Parscal 2011-02-15 22:15:01 UTC
r82200 takes a stab at this. More could be done like this.
Comment 3 Mark A. Hershberger 2011-02-17 00:27:51 UTC
I *think* this is takes care of the most visible problem, so I'm removing the blocker.  Since Trevor's comment implies more could be done, not closing it.
Comment 4 Bugmeister Bot 2011-08-19 19:12:57 UTC
Unassigning default assignments.

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