Is there any other way to recieve block broadcasts besides the web socket? I'm trying to impliment it low-level and I keep getting "GET requests are not supported on this server" etc.
You can poll
http://blockchain.info/latestblock, other than that i'm not sure. That error message probably means you are not including the proper "Upgrade: WebSocket" header in http request and it is being interpreted as a normal GET.
Don't know how relevant it is to you (I think you asked above), but javascript can be embedded in CSS as well using the 'javascript:' scheme in a url().
Found a test page at
http://krijnhoetmer.nl/stuff/css/url-javascript-opera-chat/ and it would not alert() in Safari, Chrome, Firefox or Opera. Maybe it would be best to run the css through the verifier anyway though.