Hello, script was always working correctly on every web browser. Unfortunately after (probably) last update Firefox stopped handling with it. Script is the part of forum based on popular MyBB (http://www.mybb.com/). I put a screenshoot below, which should easily show how did the script work. http://screenshooter.net/data/uploads/ug/tg/dyre.jpg After clicking on any icon (e.g. bold "B") it shows "[undefined=undefined]" and then clicking shows no effects. Errors from "WWW console" after icon clicking: TypeError: mnu is undefined - line 641 TypeError: tag is undefined - line 1163 Here I posted problematic script: http://pastebin.com/D8HmLEKK Best regards!