function SetCwinHeight(obj) {
var cwin = obj;
if (document.getElementById) {
if (cwin && !window.opera) {
if (cwin.contentDocument && cwin.contentDocument.body.offsetHeight)
cwin.height = cwin.contentDocument.body.offsetHeight + 30;
else if (cwin.Document && cwin.Document.body.scrollHeight)
cwin.height = cwin.Document.body.scrollHeight + 30;
}
}
}

<iframe id="IframeId_help" scrolling="no" onload="Javascript:SetCwinHeight(this)"
width="670px" style="border: 0px" frameborder="0"></iframe>