[zoliky]

I write a function to handle javascript "addEventListener" for Firefox and Internet Explorer:

1: function addEvent(element, event, eventListener)
2: {
3:  if (typeof(element.addEventListener) != "undefined")
4:  {
5:    element.addEventListener(event, eventListener, false);
6:  }
7:  else
8:  {
9:    var thisListener = function()
10:   {
11:   var event = window.event;
12:   
13:             if (Function.prototype.call)
14:   {
15:    eventListener.call(element, event);
16:   }
17:  };
18:  
19:  element.attachEvent("on" + event, thisListener);
20: }
21: } 

I get the code between line 9: and 17: from web. I don't know, is a good idea to create a function (object) like this inside addEvent function? Exist a better way to do this?

Thanks

[Vicious]

it looks pretty good to me. If it works, then I wouldn't search for a better way. There is one tricky bit though:

In IE, you can attach multiple eventlisteners to one event, without one overwriting the other. In Firefox, it is possible to only add 1 eventlistener to the event. Good thing about the firefox approach is that if you forget to remove an eventlistener before adding one, then you won't have unexpected results. In IE however, it is possible that multiple functions are triggered.

To circumvent that, you have to find a way to make sure that only 1 eventlistener is triggered for a particular event. (in IE)

[zoliky]

thanks, but what "var thisListener = function()" do exactly, create a function or object ?

This is not better: ?

function addEvent(element, event, eventListener)
{
    if (typeof(element.addEventListener) != "undefined")
    {
        element.addEventListener(event, eventListener, false);
    }
    else
    {
        function thisListener()
        {
            var event = window.event;
            
            if (Function.prototype.call)
            {
                eventListener.call(element, event);
            }
        }
 
element.attachEvent("on" + event, thisListener);
} 

The both method work for me.. But I don't know is a good idea to define a function in another function ?

[Vicious]

A function. It's only an object if you give the function properties.

var listener = function(){alert("foo");};
alert(typeof listener);
 
function listener2(){
alert("bar");
}
alert(typeof listener2);