XPerT:
You've just stated the major problem with navigation systems like this... They're not very cross-brower compatible. Internet Explorer is a VERY forgiving browser, and it's got a ton of proprietary features that allow it to do stuff that no other browser can do. And since the majority of people now use IE, many scripts get made either specifically for, or optimized for, IE.
Menus are particularly bad at this. The menu system at UBBDev is completely nonfunctional in Opera 5, and has only recently been upgraded to be functional in Netscape 6. I myself used to use dropdown menus for navigation, but I've since made major attempts to keep my site relatively compatible with all major browsers, so I've stopped using them.
---Skorpion
