AddEventListener For IE 5+

This makes my life a bit easier. After executing this script you should be able to addEventListener on all elements instead of determining if you want to call attachEvent or addEventListener.
Edit: This is the original version. The revised version is below
if (!document.addEventListener && document.attachEvent)
{
Object.prototype.addEventListener = function(eventName, func, capture)
{
if (this.attachEvent)
this.attachEvent('on' + eventName, func);
}

var i, l = document.all.length;

for (i = 0; i < l; i++)
document.all[i].addEventListener = Object.prototype.addEventListener;

window.addEventListener = Object.prototype.addEventListener;
document.addEventListener = Object.prototype.addEventListener;
}

Revised version:

This one is harder to use but it is nicer to the DOM and all newly created objects. The problem with it is that addEventListener will only be available after the page loads.

If you want to use addEventListener from a window.onload script make sure that this code is included in the body, not in the head. document.body.onload is called before window.onload.

Now, only elements that already have attachEvent will get an addEventListener. Elements created with document.createElement will automatically get addEventListener.

function createIEaddEventListeners()
{
if (document.addEventListener || !document.attachEvent)
return;

function ieAddEventListener(eventName, handler, capture)
{
if (this.attachEvent)
this.attachEvent('on' + eventName, handler);
}

function attachToAll()
{
var i, l = document.all.length;

for (i = 0; i < l; i++)
if (document.all[i].attachEvent)
document.all[i].addEventListener = ieAddEventListener;
}

var originalCreateElement = document.createElement;

document.createElement = function(tagName)
{
var element = originalCreateElement(tagName);

if (element.attachEvent)
element.addEventListener = ieAddEventListener;

return element;
}

window.addEventListener = ieAddEventListener;
document.addEventListener = ieAddEventListener;

var body = document.body;

if (body)
{
if (body.onload)
{
var originalBodyOnload = body.onload;

body.onload = function()
{
attachToAll();
originalBodyOnload();
};
}
else
body.onload = attachToAll;
}
else
window.addEventListener('load', attachToAll);
}

createIEaddEventListeners();