<script type="text/javascript">
/***
* IFrame SSI script II- © Dynamic Drive DHTML code library (http://www.dynamicdrive.com)
* Visit DynamicDrive.com for hundreds of original DHTML scripts
* This notice must stay intact for legal use
***/
//Input the IDs of the IFRAMES you wish to dynamically resize to match its content height:
//Separate each ID with a comma. Examples:  or  or  for none:
var iframeids=
//Should script hide iframe from browsers that don't support this script (non IE5+/NS6+ browsers. Recommended):
var iframehide="yes"
var getFFVersion=navigator.userAgent.substring(navigator.userAgent.indexOf("Firefox")).split("/")
var FFextraHeight=parseFloat(getFFVersion)>=0.1? 16 : 0 //extra height in px to add to iframe in FireFox 1.0+ browsers
function resizeCaller() {
var dyniframe=new Array()
for (i=0; i<iframeids.length; i++){
if (document.getElementById)
resizeIframe(iframeids)
//reveal iframe for lower end browsers? (see var above):
if ((document.all || document.getElementById) && iframehide=="no"){
var tempobj=document.all? document.all] : document.getElementById(iframeids)
tempobj.style.display="block"
}
}
}
function resizeIframe(frameid){
var currentfr=document.getElementById(frameid)
if (currentfr && !window.opera){
currentfr.style.display="block"
if (currentfr.contentDocument && currentfr.contentDocument.body.offsetHeight) //ns6 syntax
currentfr.height = currentfr.contentDocument.body.offsetHeight+FFextraHeight; 
else if (currentfr.Document && currentfr.Document.body.scrollHeight) //ie5+ syntax
currentfr.height = currentfr.Document.body.scrollHeight;
if (currentfr.addEventListener)
currentfr.addEventListener("load", readjustIframe, false)
else if (currentfr.attachEvent){
currentfr.detachEvent("onload", readjustIframe) // Bug fix line
currentfr.attachEvent("onload", readjustIframe)
}
}
}
function readjustIframe(loadevt) {
var crossevt=(window.event)? event : loadevt
var iframeroot=(crossevt.currentTarget)? crossevt.currentTarget : crossevt.srcElement
if (iframeroot)
resizeIframe(iframeroot.id);
}
function loadintoIframe(iframeid, url){
if (document.getElementById)
document.getElementById(iframeid).src=url
}
if (window.addEventListener)
window.addEventListener("load", resizeCaller, false)
else if (window.attachEvent)
window.attachEvent("onload", resizeCaller)
else
window.onload=resizeCaller
</script>

<iframe id="iframe" src="x.html" scrolling="no" marginwidth="0" marginheight="0" frameborder="0" vspace="0"
hspace="0" style="overflow:visible; width:100%; display:none;"></iframe>

<a href="javascript:loadintoIframe('myframe', 'external.htm')">Link</a>