Making buttons run scripts

[Æ№∞₧]

What is the easiest way to make buttons run scripts?
IE, When X is pressed, run... But on ALL MAPS.

Also, what is the easyest way to edit which button do what?
IE, X opens menu, Y is action button

 

[Velocir_X]

Well if you hit F1 while playing you can see which input is mapped to which keys
then in scripts for things such as menu you can look for line
Input::<some input>

 

[Æ№∞₧]

Which script? I would rather have a common even running.

 

[Velocir_X]

It depends what you're trying to change...
for example menu is: Scene_Menu

As for common event it will run slower but hey...
just make it:
Parallel Process
Conditional branch (some button is pressed)
(preform whatever action)
End

And I don''t believe you can change the action button
(though I may be wrong it could be in some script)