jQuery UI Sortable, then write order into a database

The jQuery UI sortable feature includes a serialize method to do this. It's quite simple, really. Here's a quick example that sends the data to the specified URL as soon as an element has changes position.

$('#element').sortable({
    axis: 'y',
    update: function (event, ui) {
        var data = $(this).sortable('serialize');

        // POST to server using $.post or $.ajax
        $.ajax({
            data: data,
            type: 'POST',
            url: '/your/url/here'
        });
    }
});

What this does is that it creates an array of the elements using the elements id. So, I usually do something like this:

<ul id="sortable">
   <li id="item-1"></li>
   <li id="item-2"></li>
   ...
</ul>

When you use the serialize option, it will create a POST query string like this: item[]=1&item[]=2 etc. So if you make use - for example - your database IDs in the id attribute, you can then simply iterate through the POSTed array and update the elements' positions accordingly.

For example, in PHP:

$i = 0;

foreach ($_POST['item'] as $value) {
    // Execute statement:
    // UPDATE [Table] SET [Position] = $i WHERE [EntityId] = $value
    $i++;
}

Example on jsFiddle.

Thought this might help as well. A) it was designed to keep payload to its minimum while sending back to server, after each sort. (instead of sending all elements each time or iterating through many elements that server might chuck out) B) I needed to send back custom id without compromising the id / name of the element. This code will get the list from asp.net server and then upon sorting only 2 values will be sent back: The db id of sorted element and db id of the element next to which it was dropped. Based on those 2 values, server can easily identify the new postion.

<div id="planlist" style="width:1000px">
    <ul style="width:1000px">
       <li plid="listId1"><a href="#pl-1">List 1</a></li>
       <li plid="listId2"><a href="#pl-2">List 1</a></li>
       <li plid="listId3"><a href="#pl-3">List 1</a></li>
       <li plid="listId4"><a href="#pl-4">List 1</a></li>
    </ul>
    <div id="pl-1"></div>
    <div id="pl-2"></div>
    <div id="pl-3"></div>
    <div id="pl-4"></div>
</div>
<script type="text/javascript" language="javascript">
    $(function () {
        var tabs = $("#planlist").tabs();
        tabs.find(".ui-tabs-nav").sortable({
            axis: "x",
            stop: function () {
                tabs.tabs("refresh");
            },
            update: function (event, ui) {
                //db id of the item sorted
                alert(ui.item.attr('plid'));
                //db id of the item next to which the dragged item was dropped
                alert(ui.item.prev().attr('plid'));

                //make ajax call
            }
        });
    });
</script>