iframe resize

Hi,
I want to resize an iframe using jquery.
Somehow the belwo code is not owrking properly for me.
Can someone help me
        function sizeIFrame() {
            var helpFrame = jQuery("#helpFrame");
            alert(helpFrame)
            var innerDoc = (helpFrame.get(0).contentDocument) ? helpFrame.get
(0).contentDocument : helpFrame.get(0).contentWindow.document;
            alert(innerDoc)
            alert(innerDoc.body.scrollHeight)
            helpFrame.height(innerDoc.body.scrollHeight + 35);
        }
        jQuery(function() {
            sizeIFrame();
            jQuery("#helpFrame").load(sizeIFrame);
        });
    </script>
    <iframe id="helpFrame" name="helpFrame" marginwidth="0"
marginheight="0"
        src="Index.tml" frameborder="0"></iframe>
Thanks