jQuery(document).ready(function(){
    jQuery("#browser").treeview();
 jQuery("#add").click(function() {
 	var branches = jQuery("<li><span class='folder'>New Sublist</span><ul>" + 
 		"<li><span class='file'>Item1</span></li>" + 
 		"<li><span class='file'>Item2</span></li>" +
 		"</ul></li>").appendTo("#browser");
 	jQuery("#browser").treeview({
 		add: branches
 	});
 });
  });