JavaScript - Media Playback Detection

gistfile1.js

// this is part of my core javascript code, it detects flash and MP4 media playback capabilities
window.core = new function() {
	var document  = window.document;
	var navigator = window.navigator;

	var flashVersion   = null;
	var flashAvailable = false;
	var audioAvailable = false; // MP4
	var videoAvailable = false; // MP4

	// new closure used to isolate variables
	new function() {
		// partial HTML5 element rendering fix for MSIE < 9
		if( /MSIE [0-8]\./.test(navigator.userAgent) ) {
			var a = [
				"article",
				"aside",
				"footer",
				"header",
				"section"
			];
			while( a.length ) {
				document.createElement( a.pop() );
			}
		}
		var o;
		var v;
		var x = /([0-9]+).([0-9]+).[a-z]?([0-9]+)/;
		try {
			o = navigator.plugins["Shockwave Flash"];
			v = o.description.match( x );
		}
		catch( error ) {
			try {
				o = new ActiveXObject( "ShockwaveFlash.ShockwaveFlash" );
				v = o.GetVariable( "$version" ).match( x );
			}
			catch( error ) {}
		}
		if( v ) {
			flashVersion = [ v[1]-0, v[2]-0, v[3]-0 ];
			flashAvailable = true;
			if( flashVersion[0] > 9 || flashVersion[0] == 9 && flashVersion[2] >= 152 ) {
				audioAvailable = true;
				videoAvailable = true;
				return; // HTML5 media elements not required
			}
		}
		o = document.createElement( "audio" );
		if( o.canPlayType ) {
			audioAvailable = o.canPlayType( "audio/mp4; codecs=\"mp4a\"" ) == "probably";
		}
		o = document.createElement( "video" );
		if( o.canPlayType ) {
			videoAvailable = o.canPlayType( "video/mp4; codecs=\"avc1,mp4a\"" ) == "probably";
		}
	}
	//
}