修正png图片不透明

function correctPNG()
   ...{
   for(var i=0; i<document.images.length; i++)
      ...{
      var img = document.images[i]
      var imgName = img.src.toUpperCase()
      if (imgName.substring(imgName.length-3, imgName.length) == "PNG")
         ...{
         var imgID = (img.id) ? "id='" + img.id + "' " : ""
         var imgClass = (img.className) ? "class='" + img.className + "' " : ""
         var imgTitle = (img.title) ? "title='" + img.title + "' " : "title='" + img.alt + "' "
         var imgStyle = "display:inline-block;" + img.style.cssText
         if (img.align == "left") imgStyle = "float:left;" + imgStyle
         if (img.align == "right") imgStyle = "float:right;" + imgStyle
         if (img.parentElement.href) imgStyle = "cursor:hand;" + imgStyle       
         var strNewHTML = "<span " + imgID + imgClass + imgTitle
         + " style="" + "width:" + img.width + "px; height:" + img.height + "px;" + imgStyle + ";"
         + "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader"
         + "(src='" + img.src + "', sizingMethod='scale');"></span>"
         img.outerHTML = strNewHTML
         i = i-1
         }
      }
   }
window.attachEvent("onload", correctPNG);