function getElementsByClass(maClass, fromTag)  {
    var tabRetour = new Array();
    var tabTmp = new Array();
    var arr_class;
    tabTmp = document.getElementsByTagName(fromTag||"*");
    var j=0;
    for (i=0; i<tabTmp.length; i++) {
        arr_class = tabTmp[i].className.split(" ");
        for(var k=0; k<arr_class.length;k++ )
            if(arr_class[k]== maClass) {
                tabRetour[j++]=tabTmp[i];
            }
    }
    return tabRetour;
}

function hackPNGbg(cl, tag)
{
 try {
    var pngs = getElementsByClass(cl,tag);
    for(i in pngs) {
       var src = pngs[i].currentStyle.backgroundImage.replace(/(url[\s]*\()+/, "");
       src=src.replace(/(\")+/g,"");
       src = src.substr(0,src.length-1);
       pngs[i].runtimeStyle.backgroundImage="url(blank.gif)";
       pngs[i].runtimeStyle.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" + 

src + "')";
    }
 } catch(e){};
}
hackPNGbg("PNGbg");