$(\"#ifTree\").jstree({
\"plugins\" : [\"themes\",\"html_data\",\"ui\",\"crrm\"],
\"themes\" : {
\"theme\" : \"apple\",
The simplest way to do this is just like adding an attribute to an html element i.e.,
var node = $.jstree._focused().get_selected(); //get the selected node or which ever you want the data to be associated with
node.attr("expression","xyz"); //add an attribute (name,value) here, name-expression and value-xyz