Sound from browsers with javascript buggy on HTC Desire?

I'm trying to stream music from The Hype Machine on my HTC Desire. When using the HTC Sense stock browser I can press play, go to menu → ... → settings → site specific settings → back out until l I arrive at the site again Only then the music will start playing. If I activate the key lock or take the focus away in any other way, the sound will stop. When using Opera Mobile I can't seem to get the sound to work at all. Looking at the site's source the streaming is done with Javascript (mootools). On my desktop I don't get any javascript errors and the site works perfectly fine. Can anybody tell me why I have to jump through such hoops with the stock browser to get the sound going, how I can have the browser keep playing in the background or with the key lock on or why the sound doesn't seem to work in the otherwise nice Opera Mobile?