[jQuery] How to define FireBug?

[mtest]

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 :)