onDomReady

// Adapted from DOM Ready extension by Dan Webb
// http://www.vivabit.com/bollocks/2006/06/21/a-dom-ready-extension-for-prototype
// which was based on work by Matthias Miller, Dean Edwards and John Resig
//
// Usage:
//
// Event.onReady(callbackFunction);
Object.extend(Event, {
  _domReady : function() {
    if (arguments.callee.done) return;
    arguments.callee.done = true;
 
    if (Event._timer)  clearInterval(Event._timer);
 
    Event._readyCallbacks.each(function(f) { f() });
    Event._readyCallbacks = null;
 
  },
  onReady : function(f) {
    if (!this._readyCallbacks) {
      var domReady = this._domReady;
 
      if (domReady.done) return f();
 
      if (document.addEventListener)
        document.addEventListener("DOMContentLoaded", domReady, false);
 
        /*@cc_on @*/
        /*@if (@_win32)
            var dummy = location.protocol == "https:" ?  "https://javascript:void(0)" : "javascript:void(0)";
            document.write("<script id=__ie_onload defer src='" + dummy + "'><\/script>");
            document.getElementById("__ie_onload").onreadystatechange = function() {
                if (this.readyState == "complete") { domReady(); }
            };
        /*@end @*/
 
        if (/WebKit/i.test(navigator.userAgent)) { 
          this._timer = setInterval(function() {
            if (/loaded|complete/.test(document.readyState)) domReady(); 
          }, 10);
        }
 
        Event.observe(window, 'load', domReady);
        Event._readyCallbacks =  [];
    }
    Event._readyCallbacks.push(f);
  }
});