[whatwg] <object>, type, and fallback

[Brady Eidson]

I can't find a definitive answer for the following scenario:

1 - A page has a plug-in with fallback specified as follows:

<object type="application/x-shockwave-flash">
<param name="movie" value="Example.swf"/>
    <img src="Fallback.png">
</object>

2 - The page is loaded, the browser instantiates the plug-in, and the plug-in content is shown.

3 - A script later comes along and dynamically changes the <object>'s type attribute to "application/some-unsupported-type"

Should the browser dynamically and immediately switch from the plug-in to the fallback image?
If not, what should it do?
And is this specified anywhere?

Thanks,
~Brady