1501354 - fetch should not block the load event

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, enhancement)

Description

[Boris Zbarsky [:bzbarsky]]

Testcase:

<script>
  onload = () => alert('load fired');
  var x = fetch("http://software.hixie.ch/utilities/cgi/test-tools/delayed-file?pause=4&mime=text%2Fplain&text=abc",
                { mode: "no-cors" });
  x.then((r) => console.log(r), (e) => console.log("FAIL: " + e));
</script>

In Gecko, we block the load event on that load.  Can we make it LOAD_BACKGROUND?  Or do we need to get progress events for these loads?

Neither Chrome nor Safari block the load event here, and the spec doesn't say to do it either.

Comment 1

[Andrea Marchesini [:baku]]

Attachment: fetch_background.patch

Comment 2

[Boris Zbarsky [:bzbarsky]]

Comment on attachment 9020314 [details] [diff] [review]
fetch_background.patch

r=me

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

oh oh, this could be rather bad for page load. Thanks for fixing.
(though, load blocking XHR seems to be still used way more often)

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/ab03a5f49397
Fetch() should not block the loadgroup from completing, r=bz

Comment 5

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/ab03a5f49397