CMS Made Simple Forums

Can someone tell me how to execute a javascript popup box from a menu item? I would like to popup a lightbox window. To be exact how do I open this box, http://leandrovieira.com/projects/jquery/lightbox/ from the menu.  Thanks. I hope this is possible and someone has some detailed info on how to do it.

Thanks for the quick response. I'm using the cssmenu template so where would I put the code below after importing to the database?
{elseif $node->type == 'link'}
url}">{$node->menutext}

It would most likely go after the...

{elseif $node->type == 'separator'}