Button Script
Every Destination Screen has a button script which indicates how the function keys the user presses or the buttons the user clicks should be handled:
When you generate a button script from tracking information, every key present on the screen is handled in a series of SENDKEY functions in the script.
...
case KeyEnter:
SENDKEY(KeyEnter);
...
If you disable a key in the Destination Screen Details the script for it does not get executed.
In most situations navigational 5250 function keys like F12=Cancel and F3=Exit should be disabled and not shown because they are not required in Windows navigation and tend to just confuse users.
You can also add buttons or function keys which are entirely processed on the client system and never sent back to the server. To do this you enable them in the Destination Screen Details and then add handling for them in the button script.
Also See: