This has done this for (years?) on CodePen in @firefox.
We have a totally normal <link rel=“stylesheet”> at the top of the page that is supposed to be render-blocking, yes?
Would love to understand.pic.twitter.com/HGTHwpemiy
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I still don’t understand why, but there is a solution for now. We didn’t have any <script>s in our <head>, so just putting one there with a comment fixes it. <script>/* Firefox needs this to prevent FOUC. */</script> </head> Hattip
@JasonEtco6 replies 3 retweets 63 likesShow this thread -
My guess is that JS is render blocking, CSS isn't. The HTML may be getting fully parsed and therefore painted before the CSS fully download. Adding the JS prevents the rendering b/c it's blocking even if empty, so browser is waiting to parse the script is executed. total guess.
1 reply 0 retweets 2 likes -
Replying to @estellevw @chriscoyier and
P sure that's true, but my grasp is the details is shaky too.
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Replying to @tabatkins @estellevw and
Firefox blocks rendering on stylesheets in the head, and also blocks script execution on them. Issues can result from things like <script defer> that runs at weird times, addons that run their own script at weird times, and perhaps some other bugs. Curious what addons in use.
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Replying to @davidbaron @tabatkins and
@bz_moz is the expert on this, though.1 reply 0 retweets 0 likes
Like I said up-thread, this ishttps://bugzilla.mozilla.org/show_bug.cgi?id=687441 …
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