The following code and tutorial can be used to set the IFrame scrolling attribute dynamically using Javascript
<html>
<head>
<title>Setting IFRAME Scrolling attribute using Javascript</title>
<script type="text/javascript">
function setIframeScroll(pge,iframeid, mode) { // mode can be either "yes" or "no"
var oldIframe = document.getElementById(iframeid);
var newIframe = oldIframe.cloneNode(true);
newIframe.scrolling = mode;
oldIframe.parentNode.insertBefore(newIframe, oldIframe);
newIframe.parentNode.removeChild(oldIframe);
document.getElementById(iframeid).src=pge;
}
</script>
</head>
<body>
<iframe id="myIframe" src="q.html" scrolling="no"></iframe>
<br />
<input type="button" value="Submit" onclick="setIframeScroll('a.html','myIframe','yes')" />
</body>
</html>