var blank = "images/blank.gif";
function pngFilter(id, imgUrl)
{
    var el = document.getElementById(id);
    
    if (!el) return;
    
    if (el.filters && imgUrl.match(/.png$/i))
    {
        el.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader( src='"+imgUrl+"', sizingMethod='scale')"; 	
		if (el.src) el.src = blank;
    }
    else
    {
	    if (el.src)
		    el.src = imgUrl;
	    else
            el.style.backgroundImage="url('"+imgUrl+"')";
    }
}