I just installed the MSIE 9 beta in a Virtual Machine, and tried to get the following to work:
<audio src="swing.mp3" autoplay=true controls=true>
Your browser does not support the audio element.
It was running fine in Chrome, but in MSIE 9 I found that the the code must be preceded by:
Then this new control shows up:
If I’m not much mistaken the same will go for the other new HTML tags like <video>, <svg> etc.
Read more here: http://msdn.microsoft.com/en-us/library/ff975061.aspx