PNG Opacity support for Internet Explorer (simplified)

//	this script have dependencies on prototype-1.4.0.js and Browser Detect Lite  v2.1
//	http://prototype.conio.net/
//	http://www.dithered.com/javascript/browser_detect/index.html
//	(cc) alvaro isorna
 
Event.observe(window, 'load', function(){
	//	this will iterate with each element with the class 'ie-fix-opacity' and add an IE filter,
	//	replacing the background-image for the filter of that image
	document.getElementsByClassName('ie-fix-opacity').each(function(poElement){
		// if IE5.5+ on win32, then display PNGs with AlphaImageLoader
		if ((browser.isIE55 || browser.isIE6up) && browser.isWin32){
			var cBGImg = poElement.currentStyle.backgroundImage;
			var cImage = cBGImg.substring(cBGImg.indexOf('"') + 1, cBGImg.lastIndexOf('"'));
 
			poElement.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + cImage + "', sizingMethod='scale')";
			poElement.style.backgroundImage = "none";
		}
	});
}, false);