Why are js png pictures (with transparency) opaque in IE6_javascript skills

复制代码 代码如下:

function correctPNG() // correctly handle PNG transparency in Win IE 5.5 & 6.
{
var arVersion = navigator.appVersion.split("MSIE")
var version = parseFloat(arVersion[1])
if ((version >= 5.5) && (document.body.filters)) {
for (var j = 0; j < document.images.length; j ) {
var img = document.images[j]
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 = " " "width:" img.width "px; height:" img.height "px;" imgStyle ";"
"filter:progid:DXImageTransform.Microsoft.AlphaImageLoader"
"(src='" img.src "', sizingMethod='scale');">"
img.outerHTML = strNewHTML
j = j - 1
}
}
}
}
window.attachEvent("onload", correctPNG);