jQuery UI Sortable: Revert changes if update callback makes an AJAX call that fails?

Question

I am using the sortable widget to re-order a list of items. After an item is dragged to a new location, I kick off an AJAX form post to the server to save the new order. How can

Answer 1

I just encountered this same issue, and for the sake of a complete answer, I wanted to share my solution to this problem:

$('.list').sortable({
  items:'.list:not(.loading)',
  start: function(event,ui) { 
    var element = $(ui.item[0]);
    element.data('lastParent', element.parent());
  },
  update: function(event,ui) {
    var element = $(ui.item[0]);
    if (element.hasClass('loading')) return;
    element.addClass('loading');
    $.ajax({
      url:'/ajax',
      context:element,
      complete:function(xhr,status) {
        $(this).removeClass('loading');
        if (xhr.status != 200) {
          $($(this).data('lastParent')).append(this);
        }
      },
    });
  }
});

You'll need to modify it to suit your codebase, but this is a completely multithread safe solution that works very well for me.