[whatwg] HTML 5 video tag questions

Boris Zbarsky bzbarsky at MIT.EDU
Tue Jul 14 02:46:08 PDT 2009

Philip Jägenstedt wrote:
> Anything that can cause the element to switch back and forth between 
> displaying fallback and video is a no-go, that would cause a race 
> condition for if plugins/images in the fallback content. If they have 
> event handlers the results will get ugly fast:
> <video>
> <!-- network lag -->
> <source>
> <!-- network lag -->
> <source>
> <!-- network lag -->
> <img src=foo onload="alert('how many times will you see this message?')">
> </video>

The answer to the question in the alert is "once".  This is true in the 
current fallback model, and would presumably be true in the new fallback 

For the current model, note that all the text says is "should not show 
this content to the user".  While this is not defined anywhere, it 
doesn't seem to indicate that the content's DOM should not exist, for 
example.  In Gecko, at least, the image in your example will be loaded 
and hence its onload will fire.


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