function doIframe(){
  o = document.getElementsByTagName('iframe');
  for(i=0;i<o.length;i++){
    if (/\bautoHeight\b/.test(o[i].className)){
      setHeight(o[i]);
      addEvent(o[i],'load', doIframe);
    }
  }
}

function setHeight(e){
  if(e.contentDocument){
    e.height = e.contentDocument.body.offsetHeight + 35;
  } else {
    e.height = e.contentWindow.document.body.scrollHeight;
  }
}

function addEvent(obj, evType, fn){
  if(obj.addEventListener)
  {
  obj.addEventListener(evType, fn,false);
  return true;
  } else if (obj.attachEvent){
  var r = obj.attachEvent("on"+evType, fn);
  return r;
  } else {
  return false;
  }
}

if (document.getElementById && document.createTextNode){
 addEvent(window,'load', doIframe); 
}