Forum Moderators: open
The solution might be to add a script to the head of the page that writes out a piece of css, which sets the display-property of the submenus to 'none'. Example:
<script type="text/javascript">
document.write('<style type="text/css">ul.submenu {display: none;}</style>');
</script>
This way js-challenged users still get to see the full menu.