IE6 reporting invalid argument when injecting PNG fix into head of document with jQuery

Am having problems with the following code reporting an 'invalid argument' in IE6.

function LoadScriptsAndExecute(url) {
    this.url = url;
    this.loadScript = function() {
        $.ajax({
            url: this.url,
            cache: true,
            dataType: 'script',
            success: function(){
                //alert(this.url);
            },
            error: function(){
                //alert('error');
            }
        }); 
        return true;                    
    }
}

// IE6 fixes | Semi-transparent PNG
if (icisSite.isIE(6, 'lte') == true) {

开发者_如何学Python    var pngFix = new LoadScriptsAndExecute("/Global/ICIS/Scripts/DD_belatedPNG_0.0.8a-min.js");
    var pngList = new LoadScriptsAndExecute("/Global/ICIS/Scripts/DD_PNG_listing.js");
    pngFix.loadScript();    
    pngList.loadScript();       
}

Am pretty sure that i won't be able to get to the bottom of this as it is reporting an invalid argument on a line that does not exist. All quite frustrating.

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I have decided that due to the constraints of the framework not to bother with this implementation and let IE6 displays semi-transparent PNG as they are.