The expand event is fired before a node is about to get expanded.
This event can be cancelled.

The following additional properties are set to the event object:
- element - the element of the node being expanded;
- item - the data source item object of the node being expanded.

<ul id="treeview">
    <li>My Project
            <li id="someid">js</li>

<script type="text/javascript">
    jQuery(function ($) {
            events: {
                expand: function(e) {
                    console.log("expanded node " + this.getPath(e.element));