jQuery plugin sortable

sortable.js

(function ($) {
  $.fn.sortable = function (options){

    options = $.extend({
      url: null
    }, options);

    return this.each(function (){
      var handle = $(this);
      var items = handle.children(options.items);
      items.attr('draggable', true);

      items.on('dragstart',function(e){
        this.style.opacity = '0.4';
        e.originalEvent.dataTransfer.setData('sourceId', $(this).attr('id'));
      });

      items.on('dragenter', function(e){
        $(this).addClass('over');
      });

      items.on('dragover', function(e){
        e.preventDefault();
      });

      items.on('dragleave', function(e){
        $(this).removeClass('over');
      });

      items.on('drop', function(e){
        e.stopPropagation();
        var sourceId = e.originalEvent.dataTransfer.getData('sourceId');
        var sourceEl = $('#' + sourceId);
        $(e.currentTarget).before(sourceEl);
        handle.children().each(function(index, el) {
          $(el).data('index', index);
        });
      });

      items.on('dragend', function(e){
        this.style.opacity = '1';
        $('div').removeClass('over');
      });
    });
  };
})(jQuery);