1886145 - Link rel preload not supported for track

Status: UNCONFIRMED

(Core :: DOM: Networking, task, P2)

Description

[Barry Pollard]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Steps to reproduce:

Open DevTools and go to this link: https://resource-loading-examples.glitch.me/preload-types.html

Note which resources are loaded and which are not in Firefox and repeat the same in Chrome and Safari.

Actual results:

Only the following types are loaded in Firefox:

• fetch
• image
• font
• script
• style

Expected results:

Well, according to HTML spec more types should be supported. So raised a question there: https://github.com/whatwg/html/issues/8332#issuecomment-2001980048

However it looks like all the browsers are nearly identical in loading a subset, except Firefox which also does not preload as=track. I don't know how much call there is for this type, but if an easy fix, then would be good to add support for this to be consistent with the other browsers.

Cause it also makes BCD data trickier than it should be:
https://github.com/mdn/browser-compat-data/pull/22658

Comment 1

[Andrew McCreight [:mccr8]]

WebVTT is under media, so I'll move this there, though maybe it should be DOM or Networking (because of preloading?). For what it is worth, I only see a single instance of the string as="track" in the tree, so I guess there's no WPT coverage for this? Or maybe it shows up in a way that a simple string search doesn't find it.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:jimm, could you have a look please?

For more information, please visit BugBot documentation.

Comment 3

[Barry Pollard]

FYI WPT has since been added: https://wpt.fyi/results/preload/supported-as-values.html%3Fas%3Dtrack%26expected%3D1?label=experimental&label=master&aligned

Also found https://bugzilla.mozilla.org/show_bug.cgi?id=1766213 for the same reason (though technically it's about the type being returned correctly).

Comment 4

[Alastor Wu [:alwu]]

This is more about HTMLLinkElement, move this bug to DOM component.