Edit in JSFiddle

<div id="vocab-tree"></div>
$("#vocab-tree").vocab_widget({
	mode:'tree',
	endpoint: 'https://vocabs.ands.org.au/apps/vocab_widget/proxy/',	repository:'anzsrc-for'})
.on('treeselect.vocab.ands', function(event) {
	var target = $(event.target);
	var data = target.data('vocab');
	alert('You clicked ' + data.label + '\r\n<' + data.about + '>');
});