[jQuery] How to define FireBug?

Hello all :)
If it possible to define Firebug? Install it or not? Like it possible
do whis browsers by command:
if ($.browser.safari) {
alert("this is safari!");
}
maybe like this :))
if ($.extensions.firebug) {
alert("FireBug is install!");
}
Thank you to attention,
and one more time sorry for my poor english:), but I try hard :)