Question

I want to run a callback function just once, it should run if it removes all elements with a certain class, but for some reason the callback function runs times the number of elements that are removed, so thats not what i am looking for.

The code(form a plugin)

     $.plugin= {
        clear: function(str){

            $('.msg').fadeOut(200, function(){
                $(this).remove();
                if(typeof str.remove == 'function'){
                    str.remove.call(this);
                }           
            });
        } 
    }   

Answer 1

The easiest way would be to unset the function:

    $('.msg').fadeOut(200, function(){
        $(this).remove();
        if(typeof str.remove == 'function'){
            str.remove.call(this);
            str.remove = false;
        }           
    }); 

---

JAAulde might be right.
The following code calls the callback with all .msg elements:

    var $msgs = $('.msg').fadeOut(200, function(){
        $(this).remove();
        if(typeof str.remove == 'function'){
            str.remove.call($msgs);
            str.remove = false;
        }           
    }); 

Note that $('.msg') is slow (especially in IE 7 and below) and should not be used without a tag.
The reason is that they don’t support document.querySelectorAll (as Mike G said)