ActiveX/HTML
You can insert the ActiveX control in your HTML pages like this :
<OBJECT classid="clsid:E23FE9C6-778E-49D4-B537-38FCDE4887D8"
codebase="http://downloads.videolan.org/pub/videolan/vlc/latest/win32/axvlc.cab"
width="640" height="480" id="vlc" events="True">
<param name="Src" value="" />
<param name="ShowDisplay" value="True" />
<param name="AutoLoop" value="False" />
<param name="AutoPlay" value="False" />
</OBJECT>
Then, using Javascript, you can select another source, or change the audio track :
document.vlc.playlistClear();
var options=[":audio-track=5"]; // select audio track 5 (=6th, 1st is 0)
document.vlc.addTarget("...",options,2,0); // replace entry 0
document.vlc.play();