var changer;

(function()
{
  addEvent("load", setup);

  function setup()
  {	  
    messages = new Array();
    messages[0] = "You haven't been on this page for very long";
    messages[1] = "Wow you've been here for a long time...thanks";
    messages[2] = "Ok, did you fall asleep?";      
    
    changer = new Changer("changing", 20000, messages);  //id of the element, the speed of the changes, and an array of messages
    addEvent("unload", function(){changer.stop_changing_text();});
  }
  
  function addEvent(ev, fun)
  {
    if (window.addEventListener)
    {
      window.addEventListener(ev, fun, false);
    }
    else
    {
      window.attachEvent("on" + ev, fun);
    }
  }
})();  

function Changer(id, speed, messages)
{
  this.i = 0;
  this.timer = null;
  this.speed = speed;
  this.messages = messages;
  
  this.element = document.getElementById(id);
          
  this.change_text();    
}

Changer.prototype.change_text = function()
{
  this.element.innerHTML = this.messages[this.i];
      
  this.i = (this.i + 1) % this.messages.length;
      
  var obj = this;
  this.timer = setTimeout(function(){obj.change_text();}, this.speed);
}

Changer.prototype.stop_changing_text = function()
{
  clearTimeout(this.timer);
}