Hello
We have checked and fixed problem in your site and now it work fine. Problem because have conflict jquery in your template and we have help you fixed it (javascript for menu)
In template in file index.php we have remove line load library jquery in line 559 (default joomla3 have library jquery so not need load it)
[script type="text/javascript" src="<?php echo $this->baseurl ?>/templates/<?php echo $this->template; ?>/js/jquery.min.js"][/script]
and in line 604 we have change variable $ to jQuery (it will help you fixed conflict to $ in library mootools)
And your site is slown load
Best regards
Bach Pham