Min PNG-fix virker ikke !

Hej...

min script her virker ikke i f.eks. browseren "opera"

transpfile="img/pix.gif";

if(window.attachEvent)window.attachEvent("onload", function(){dohIE_png(document)});

function dohIE_png(tn){

  tn=tn.getElementsByTagName("img");
  for(i=0;i<tn.length;){

    if((tn[i].src.substring(tn[i].src.length-3).toLowerCase()=="png")&&tn[i].offsetWidth!=0&&tn[i].rel!="pngfixed"){

      tmp=document.createElement("img");
      tmp.style.width=tn[i].offsetWidth+"px";
      tmp.style.height=tn[i].offsetHeight+"px";
      tmp.style.border="0";
      tmp.src=transpfile;
      tmp.setAttribute("rel","pngfixed");
      if(tn[i].id)tmp.setAttribute("id",tn[i].id);
      if(tn[i].alt)tmp.setAttribute("alt",tn[i].alt);
      if(tn[i].className)tmp.setAttribute("className",tn[i].className);
      if(tn[i].title)tmp.setAttribute("title",tn[i].title);
      tmp.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+tn[i].src+"', sizingMehod='scale')";
      tn[i].parentNode.replaceChild(tmp,tn[i]);

    }else i++

  }

}