Dynamically Resize an IFrame in Firefox AND IE

So this is a big mystery out there on the net. There are a ton of silly solutions that half work. This one works for me on IE 6 & 7 and Firefox 2.x. I haven't tried it on anything else. Firefox actually accomplishes all this easily; just set the height of the IFrame to 100%. IE, on the other hand, won't behave. The IFrame needs to be inside a table, and sized to 100% to fill the table. Then you have to alter the size of the table. This doesn't work in FireFox though.

/* Dynamic Resizer v1.1 by Peter Vieth
   Resizes iframe(s) to be the same size as their content by attaching onload events for each browser 
   ATTACH THE FOLLOWING EVENT TO YOUR IFRAME (here called reportIFrame) */
if(window.addEventListener)  // Mozilla, FF, NS
  reportIFrame.addEventListener('load', resizeEvent, false) ;
else // IE
  reportIFrame.attachEvent('onreadystatechange', resizeEvent ); 

/* Bug fix for IE (added v1.1):  IFrames created by JavaScript don't actually have a "name" in IE's internals */
if(document.all) {
        if(self.frames[reportIFrame.id].name!=reportIFrame.name) 
                self.frames[reportIFrame.id].name = reportIFrame.name;
}

/* HERE IS THE EVENT DEFINITION */

function resizeEvent(evt) {
  var ieKey = "srcElement";
  var mozKey = "currentTarget";
  var IFrameObj;
  evt[mozKey] ? IFrameObj = evt[mozKey] : IFrameObj = evt[ieKey];
  fitIframe(IFrameObj);
}

/* THIS FUNCTION FITS THE IFRAME TO DOCUMENT SIZE */

function fitIframe(IFrameObj) {
var IFrameDoc;
if (IFrameObj.contentDocument) {
  // For NS6
  IFrameDoc = IFrameObj.contentDocument;
  IFrameObj.style.height=(parseInt(IFrameDoc.height)+50)+"px";
  //alert('detected NS6');
} else if (IFrameObj.contentWindow) {
  // For IE5.5 and IE6
  IFrameDoc = IFrameObj.contentWindow.document;
  if(IFrameDoc.body!=null) { // the IE event fires too often, and fires before IFrame is loaded, in which case doc==null.  It fires AGAIN once it loads fully, so ignore the first time
   try {
       var table = document.getElementById(IFrameObj.parentName);
   } catch (e) { alert('IE5.5+: Unable to located IFrames parent table: '+IFrameObj.parentName ); }
   try {
var height=parseInt(IFrameDoc.body.clientHeight)+20;
table.style.height=height;
      } catch (e) { alert('IE5.5+: Unable to get size of IFrame: '+IFrameObj.name ); }
  } // if IFrameDoc!=null

} else if (IFrameObj.document) {
  // For IE5
  IFrameDoc = IFrameObj.document;
  try {
document.getElementById(IFrameObj.parentName).style.height=IFrameDoc.body.scrollHeight-IFrameDoc.body.offsetHeight;
  } catch (e) { alert('IE 5.0: Unable to located IFrames parent table or get size of IFrame: '+IFrameObj.parentName ); }

} else {
  alert('fitIframe was unable to detect the browser version');
  return true;
}
}