Mac getURL in Actionscript 2.0

I have a flash file upload script that calls a JavaScript function using the getURL

getURL("javascript:updatealbumcover('"+editalbumid+"');");

this function works on PC using FF, IE and Safari but when i try it on my Mac it does not work is there a work around for this?

here is myjavascript:

function updatealbumcover(albumid)
{
xmlHttp=GetXmlHttpObject()
var url="/modules/useralbumhistory/updatealbumcover.php"
url = url+"?albumid="+albumid;
xmlHttp.onreadystatechange = updatealbumcoverimage
xmlHttp.open("Post",url,true)
xmlHttp.send(null)

}

here is my html :

<embed src="fileupload.swf" FlashVars="albumid=<? echo $output->id[$c]; ?>" quality="high" bgcolor="#ffffff" width="325" height="115" name="myflashvars" align="middle" allowScriptAccess="sameDomain" type="application/x-shockwave-flash" pluginspage="http://www.adobe.com/go/getflashplayer" />