source: extensions/Panoramas/jquery.animated.innerfade/win_png.htc @ 4063

<public:component>
<public:attach event="onpropertychange" onevent="propertyChanged()" />
<script>

var supported = /MSIE (5\.5)|[6789]/.test(navigator.userAgent) && navigator.platform == "Win32";
var realSrc;
var blankSrc = "rien.gif";

if (supported) fixImage();

function propertyChanged() {
        if (!supported) return;

        var pName = event.propertyName;
        if (pName != "src") return;
        // if not set to blank
        if ( ! new RegExp(blankSrc).test(src))
                fixImage();
};

function fixImage() {
        // get src
        var src = element.src;

        // check for real change
        if (src == realSrc) {
                element.src = blankSrc;
                return;
        }

        if ( ! new RegExp(blankSrc).test(src)) {
                // backup old src
                realSrc = src;
        }

        // test for png
        if ( /\.png$/.test( realSrc.toLowerCase() ) ) {
                // set blank image
                element.src = blankSrc;
                // set filter
                element.runtimeStyle.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='" +
                        src + "',sizingMethod='image')";
        }
}

</script>
</public:component>