The HTMLMediaElement.load()[1] method currently cancels playback of the
current resource and runs the resource selection algorithm[2] (and in
turn the resource fetch algorithm[3]). When preload="none", however, the
resource fetch algorithm doesn't require the UA to load data or progress
to HAVE_METADATA--instead it can suspend the load until, for example,
the user goes to play the video.
In Firefox we've hit compatibility issues where some sites are calling
load() on preload="none" resources and expecting to get a
"loadedmetadata" event.[4]
Apparently, even with preload="none", Chrome and IE progress to
HAVE_METADATA when load() is called. Presto, apparently, does not.
I've just landed a patch in Firefox to make a call to load() treat
preload="none" as preload="metadata" to match the behavior of Chrome/IE
in this case.
(Note that we need to do this not only when preload="none" is explicitly
specified but also when the preload attribute is missing and the UA's
missing value default for preload is 'none'--as is the case for us on
mobile.)
Is it possible to get this reflected in the spec?
Best regards,
Brian
[1]
https://html.spec.whatwg.org/multipage/embedded-content.html#dom-media-load
[2]
https://html.spec.whatwg.org/multipage/embedded-content.html#concept-media-load-algorithm
[3]
https://html.spec.whatwg.org/multipage/embedded-content.html#concept-media-load-resource
[4] https://bugzilla.mozilla.org/show_bug.cgi?id=1165203
