function setDropdownOpacity(element, opacity){
	if(element !== null){
		bgColor = element.getStyle('backgroundColor');
		
		isIE6 = /MSIE 6/i.test(navigator.userAgent);
	
		if(AC.Detector.isIE() && !isIE6){
			width = element.getWidth();
			height = element.getHeight();
		
			element.setStyle({'z-index':'200','backgroundColor':'transparent','height':height,'width':width});
			element.absolutize();
			
			var id = element.getAttribute('id') + '-opacity';
			var bgEl = new Element('div',{'id':id, 'style':"width:"+width+"px; height:"+height+"px; position: absolute; background-color: "+bgColor+"; top: 0; left: 0; z-index: -1;"});
			bgEl.setOpacity(opacity);
			element.insert({'top':bgEl});
		} else {
			rgba = bgColor.split('rgb(');
			if(rgba[1]){
				rgba = rgba[1].split(')');
				rgba = 'rgba('+rgba+opacity+')';
				element.setStyle({'backgroundColor':rgba});
			} else {
				return false;
			}
		}
	}
};