前端问题——png图片在IE6下透明失效，解决办法

 1 if (!window.XMLHttpRequest) {
 2     window.attachEvent("onload", enableAlphaImages);
 3 }
 4 
 5 function enableAlphaImages(){
 6     for (var i=0; i<document.all.length; i++){
 7             var obj = document.all[i];
 8             var bg = obj.currentStyle.backgroundImage;
 9             var img = document.images[i];
10             if (bg && bg.match(/\.png/i) != null) {
11                 var img = bg.substring(5,bg.length-2);
12                 var offset = obj.style["background-position"];
13                 obj.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src=‘"+img+"‘, sizingMethod=‘crop‘)";
14                 obj.style.background = "none";
15         } else if (img && img.src.match(/\.png$/i) != null) {
16             var src = img.src;
17             img.style.width = img.width + "px";
18             img.style.height = img.height + "px";
19             img.style.filter ="progid:DXImageTransform.Microsoft.AlphaImageLoader(src=‘"+src+"‘, sizingMethod=‘crop‘)"
20             img.src = "http://s1.95171.cn/b/img/pixel.gif";
21         }
22     }
23 }