Question

I have three connected sortable lists using JqueryUI: list1, list 2 and list 3. Particular items in List 1 have the class number. If these number items are dragged then they can only be dropped into list 2 BUT NOT into list 3. How do I find out which list I am about to drop it in?

$("#list1").sortable({
    start: function(event, ui) { 
        beforeStop: function (event, ui) {
            if ($(ui.item).hasClass("number")) {
                //Check which list is targeted
                //If List 3 then 
                //$(List 3).sortable('cancel');
                //End If
            }
        }
    }
});

Answer 1

You could check the item on the update event. From the jQuery documentation:

This event is triggered when the user stopped sorting and the DOM position has changed.

Something like this might work for you:

update: function (e, ui) {
    var target = ui.item;
    var parent = item.closest('ul');
    if (parent.hasClass('thirdList')) {
        // do stuff
    }
    else {
        // do stuff
        return false;
    }
}

From what I understand of your situation, I don’t think it would be necessary to check for the class number, since you can allow sorting for only the items that have class number.

Edit:

If you don’t want to be able to drag into list 3 at all, you can just not make it sortable from when the page loads and have the other lists sortable:

$(function () {
    $('#list1').sortable({
        items: '.number'
    });
    $('#list2').sortable();
});