In order to prevent these browsers from attempting to initialize menus that they can't use, a special template conditional is used.
$show['popups']
By surrounding all vBMenu controls and popups in a conditional that checks the value of $show['popups'], Javascript errors can be avoided, and alternative HTML can be shown to browsers that can't use popups.
For example:
<if condition="$show['popups']">
<!-- content here is for browsers that
are able to use the vBMenu system -->
<else />
<!-- content here is shown to browsers
that are unable to use vBMenu popups -->
</if>