Question

I am having an issue related jQuery draggable and droppable. Here is description something what I want to do.

First: I have two divs. One is <div id="selected"> and another is <div id="container">. “container” has 10 <li> which are draggable and droppable into “selected”. Here is code:

<div id="selected">
    <ul class="sortable-list">
    </ul>
</div>


<div id="container">
    <ul class="sortable-list">
             <li>1</li>
             <li>2</li>
             <li>....</li>
             <li>9</li>
             <li>10</li>
    </ul>
</div>

Second: I want to allow any 5 <li>s from “container” to “selected” div. If someone tries to add 6th <li>, then it must not allow user to it. That is the 6th <li> that is going to be inserted into “selected” must be reverted using jQuery draggable option revert.

i.e. $("#container li").draggable({ revert: true });
Here is javascript code for that.

$(document).ready(function(){

    var total = 0;
    $("#selected").droppable({
        drop: function() {
                total = $("#selected li").length;
                //alert(total);
                if (total >= 5) {
                    $("#container li").draggable({ revert: true });
                } else {
                            // below code is not working
                    $("#container li").draggable({ revert: false }); // this is making whole feature weird. I can drag all the <li> anywhere
                }
            }
    });
});

This is working fine.

Third: But when I drag an <li> from “selected” to “container”, the “selected” div will have only 4 <li>s. So in this situation, later on user should be able to add another <li> into “selected” div from “container” div. But unfortunately it is not working. All the <li>s I try to drag and drop into “selected” are being reverted due to if (total >= 5 ) condition.

Can anyone help me to solve this out using draggable revert option? Please…

Answer 1

You can use the accept option which takes a function to do this much easier, like this:

$("#selected ul").droppable({
    accept: function() {
        return $("#selected li").length < 5;
    }
});

You can test it out here. When you drag elements out, the .length goes down and it’ll accept elements again…no reason to get any more complicated 🙂