解决ie6下png的透明背景问题

/*----解决ie6下png的透明背景问题----*/
        var clear="Content/Images/clear.gif"; //path to clear.gif
        document.write('<script type="text/javascript" id="ct" defer="defer" src="javascript:void(0)"><\/script>');
        var ct=document.getElementById("ct");
        ct.onreadystatechange=function(){pngfix()};
        pngfix=function(){
            var els=document.getElementsByTagName('*'),ip=/\.png/i,al="progid:DXImageTransform.Microsoft.AlphaImageLoader(src='",i=els.length,uels=new Array(),c=0;
            while(i-->0){
                if(els[i].className.match(/unitPng/))
                {
                    uels[c]=els[i];c++;
                 }
             }
             if(uels.length==0){
                pfx(els);
             } else{
                pfx(uels);
             }
             function pfx(els){
                i=els.length;
                while(i-->0){
                    var el=els[i],es=el.style,elc=el.currentStyle,elb=elc.backgroundImage;
                    if(el.src&&el.src.match(ip)&&!es.filter){
                        es.height=el.height;es.width=el.width;es.filter=al+el.src+"',sizingMethod='crop')";
                        el.src=clear;
                    }else{
                        if(elb.match(ip)){
                            var path=elb.split('"'),rep=(elc.backgroundRepeat=='no-repeat')?'crop':'scale',elkids=el.getElementsByTagName('*'),j=elkids.length;es.filter=al+path[1]+"',sizingMethod='"+rep+"')";
                            es.height=el.clientHeight+'px';es.backgroundImage='none';
                            if(j!=0){
                                if(elc.position!="absolute")es.position='static';
                                while(j-->0)
                                    if(!elkids[j].style.position)elkids[j].style.position="relative";
                                }
                            }
                        }
                    }
             };
          };
           /*----解决ie6下png的透明背景问题----*/