Handling 'onclick' events in New SmugMug

I previously had a custom navigation menu that used an inline "onclick" event to show some additional menu items. Now, it seems that there's no way to use either javascript - even for somewhat native functions like "onclick." Has anyone found a good way to achieve something like this:

<div id="headerMenu" onclick="(document.getElementById('verticalMenu').style.display == 'block') ?   document.getElementById('verticalMenu').style.display = '' : document.getElementById('verticalMenu').style.display = 'block';">
    	menu
</div>

in the new SmugMug? In my example I want to embed my custom menu in my custom header - something I can't seem to do with any combination of html/css blocks and the built-in navigation block. This one issue aside - I'm really enjoying all of the changes!