cross browser addEventListener

bindEvent.js

// as prototype
Object.prototype.bindEvent = function(event, callback, bubble) {
    var elem = this,
        addListener    = elem.addEventListener    || elem.attachEvent,
        removeListener = elem.removeEventListener || elem.detachEvent,
        eventName;
  
    // custom "event" for ready
    if (event === 'ready') {
        eventName = document.addEventListener ? "DOMContentLoaded" : "onreadystatechange";
    } else {
        eventName = document.addEventListener ? event : "on"+event;
    }
    
    // document.ready specific
    if (elem === document && event === 'ready') {
        if (document.readyState === "complete" || document.readyState === "loaded") {
          callback();
          return;
        }
    }
  
    bubble = bubble || false;
    addListener.call(elem, eventName, function(event){
        // remove listner in document.ready
        if (elem === document && event === 'ready') {
            removeListener(eventName, arguments.callee, bubble);
        }
        callback();
    }, bubble);
};

// document.ready example
document.bindEvent('ready', function(){
    alert('moo');
});
 
// click example
document.getElementById('test').bindEvent('click', function(){
    alert('moo');
});