Jquery Droabble Box Limit

I am trying to make a drag drop stage using Jquery, I am having problem that I want only a single item inside the droppable box. But right now, it is adding multiple items inside it. Here is my code.

$("#item_list_2" ).droppable({
        drop:
                function(e, ui)
                {
                    var param = $(ui.draggable).attr('src');
                    var div_id = '#'+ $(this).attr("id");

                    addlist(param,div_id);
                }
});

Where addlist() is a function which is creating item contents using ajax. I there any way that I can restrict my #item_list_开发者_JAVA百科2 to get only one droppable object.

Thanks

You can implement the accept option in droppable to disable it when you have an element already dropped (you have to implement that condition depending on your case):

$("#item_list_2" ).droppable({
        accept: function() {
            return elementsAlreadyDropped == 0;   //<-- Implement for your concrete case
        },
        drop:
                function(e, ui)
                {
                    var param = $(ui.draggable).attr('src');
                    var div_id = '#'+ $(this).attr("id");

                    addlist(param,div_id);
                }
});