var arVer = navigator.appVersion.split("MSIE");
var ver = parseFloat(arVer[1]);
if ((ver >= 5.5 && ver < 7.0)) {
	window.attachEvent("onload", enableAlphaImages);
}
/*
if (navigator.platform == "Win32" && navigator.appName == "Microsoft Internet Explorer" && window.attachEvent) {
window.attachEvent("onload", enableAlphaImages);
}
*/

function enableAlphaImages(){
var rslt = navigator.appVersion.match(/MSIE (\d+\.\d+)/, '');
var itsAllGood = (rslt != null && Number(rslt[1]) >= 5.5);
if (itsAllGood) {
for (var i=0; i<document.all.length; i++){
var obj = document.all[i];
var bg = obj.currentStyle.backgroundImage;
var img = document.images[i];
if (bg && bg.match(/\.png/i) != null) {
var img = bg.substring(5,bg.length-2);
var offset = obj.style["background-position"];
obj.style.filter =
"progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+img+"', sizingMethod='image')";
obj.style.backgroundImage = "url('images/blank.gif')";//替换透明PNG的图片
obj.style["background-position"] = offset; // reapply
} else if (img && img.src.match(/\.png$/i) != null) {
var src = img.src;
img.style.width = img.width + "px";
img.style.height = img.height + "px";
img.style.filter =
"progid:DXImageTransform.Microsoft.AlphaImageLoader(src='"+src+"', sizingMethod='image')"
img.src = "images/blank.gif";//替换透明PNG的图片
}
}
}
}