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
}
}
}
function alphaBackgrounds(){
var rslt = navigator.appVersion.match(/MSIE (d+.d+)/, '');
var itsAllGood = (rslt != null && Number(rslt[1]) >= 5.5);
for (i=0; i<document.all.length; i++){
var bg = document.all[i].currentStyle.backgroundImage;
if (bg){
if (bg.match(/.png/i) != null){
var mypng = bg.substring(5,bg.length-2);
document.all[i].style.filter =
"progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+mypng+"',
sizingMethod='crop')";
document.all[i].style.backgroundImage = "url('')";
}
}
}
}
if (navigator.platform == "Win32" && navigator.appName == "Microsoft Internet Explorer"
&& window.attachEvent) {
window.attachEvent("onload", correctPNG);
window.attachEvent("onload", alphaBackgrounds);
}

* 注：1.当页面全部加载完成前，png图片的透明部分会显示为蓝色；

???????? 2.遍历所有元素，执行效率不高；

???????? 3.当png是以背景形式插入网页时，他可能有background-position和background-repeat属性，而滤镜不支持这两种属性，如设置了将失效。