Javascript Execute After Page Render IE6

I am having trouble with some JavaScript running before the page is completely rendered in IE 6 (maybe other versions too but just testing IE6 for now. Firefox seems to be OK). I can get around this by calling the js on window.onload like this:

window.onload = function(){doIt();}

However, my concern is the fact that I will overwrite anything else that may already be in window.onload. The code will be used as part of a library so I can not guarantee that window.onload will not be set somewhere else by someone else. I would rather append my function to the onload event like this:

window.onload += function(){doIt1();}
window.onload += function(){doIt2();}

But when I do so, only doit2() is called. Is there a way to register an event handler for when开发者_StackOverflow the page is fully rendered? My second thought would be to just put my code in a loop checking to make sure all my objects exist before running. But I am scared that this could potentially lockup the browser.

Just for some background info, my code is hiding/showing iFrames. I know that I can use the iFrame's onload attribute but I need all of the iFrames to be fully loaded before calling the code.

Any thoughts from the community? Thanks in advance for you input.

Use this generic addLoadEvent function...

function addLoadEvent(func) {
  if(typeof window.onload != 'function')
    window.onload = func;
  else {
    var oldLoad = window.onload;

    window.onload = function() {
      if(oldLoad) oldLoad();
      func();
    }
  }
}

This essentially queues up functions to be executed. It never overwrites a previously assigned handler. Sample usage below...

addLoadEvent(function() { alert("One!"); });

addLoadEvent(two);
function two() {
  alert("Two!");
}

I want to mention that libraries like jQuery take care of known issues like this for you.