ui.sortable - IE Bug in serialize with custom attribute

Serializing a sortable in IE with a custom attribute as option returns nothing.

example:

$('.groupWrapper').sortable('serialize', { attribute: 'class' });

I've experimented with ui.sortable.js and found a workaround for this.

Replace line 114 in ui.sortable.js

var res = (this.getAttribute(o.attribute || 'id') || '').match(o.expression || (/(.+)[-=_](.+)/));

with the following:

var res = ($(this).attr(o.attribute || 'id') || '').match(o.expression || (/(.+)[-=_](.+)/));