Følgende skulle give en idé til hvordan dette problem kan løses (ikke elegant og generisk, men derimod tilpasset den specifikke streng du har vist):
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "
http://www.w3.org/TR/html4/loose.dtd"><html>
<head>
<title>split function parameters</title>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1">
<script language="javascript">
function splitParams()
{
var frm = document.getElementById("frm");
var v = frm.elements["string2split"].value;
var vs = v.split(',');
document.getElementById("url1").innerHTML = vs[0].substr(vs[0].indexOf('\''));
document.getElementById("width1").innerHTML = vs[1];
document.getElementById("height1").innerHTML = vs[2].substr(0,vs[2].lastIndexOf('\'')+1);
}
</script>
</head>
<body>
<form id="frm">
<input type="text" name="string2split" id="string2split" value="return PopUpWindow('default.asp?PageID=43','300','800');" />
<input type="button" name="cmd" value="split" onclick="splitParams()" />
</form>
<span id="url1"></span><br>
<span id="width1"></span><br>
<span id="height1"></span><br>
</body>
</html>