Wait until a window does not exist

[qwertylol]

Do

Sleep (1000)

Until WinExists ( "Firefox" ) == 0

What I want to to wait until a window DOES NOT exist, yet we don't have a command ready to do that.

The above does not work. How do I do it properly?

[Generator]

Do

Sleep(1000)

$WinExist=WinExists("Firefox")

Until $WinExist=0

[PsaltyDS]

Or...

WinWaitClose("Firefox")

[gamerman2360]

Opt("WinTitleMatchMode", 2)
Do
Sleep (1000)

Until WinExists ( "Firefox" ) == 0

[ResNullius]

Or more concisely :

Opt("WinTitleMatchMode", 2)
Do
Sleep (1000)

Until NOT WinExists ( "Firefox" )

I use this kind of construct all the time and find the "NOT" makes code a little easier to follow