There are a number of instances when TextTrack::mode should be changing and we are not handling *most* if not all of them. http://www.whatwg.org/specs/web-apps/current-work/multipage/the-video-element.html#text-track-mode
A number of bugs have since resolved this.
Verified with the following steps on latest Aurora 31.0a2 (Build ID: 20140604004003) on Windows 7 x64, Mac OS X 10.9.3 and Ubuntu 13.04 x64: 1. Opened a HTML page which contains: <video src="http://people.mozilla.org/~rgiles/2013/demo.webm" controls > <track src="sample.vtt" default="" kind="subtitles" srclang="en" label="English" /> </video> and the corresponding sample.vtt file saved in the same folder 2. I used the following snippet in Scratchpad to test this: var videoElement = document.querySelector("video"); var textTracks = videoElement.textTracks; var textTrack = textTracks; var kind = textTrack.kind textTrack.mode="disabled" var mode = textTrack.mode Everytime I call for the value of textTrack.mode in the Web Console, I get the correct result, according to the specified state: - if textTrack.mode="disabled": disabled state is displayed in Web Console - if textTrack.mode="hidden": hidden state is displayed - if textTrack.mode="showing": showing state is displayed Rick, do you have any other ideas on how to verify this? Or if there's something I missed while using the method of verification I just described, please let me know.
Sure: - If you set the 'default' flag on the HTML track then the track's text track's mode should be set to 'showing' - If you set the kind of a HTML track to 'metadata' then that track's text track's mode should be set to 'hidden' - If you don't set a 'default' flag on the HTML track then the track's text track's mode should be 'hidden' Otherwise, verifying that it's setter works, like you've done, is enough. Thanks for testing it! :-)