The changed() function returns a boolean value indicating whether any of the non-button fields in a window or form have been changed by the user since the window or form was opened or the clear changes statement was run.
changed([form | window] name)
• form|window – The type of resource you’re checking.
• name – The name of the form or window to be checked.
A typical use for this function is to ascertain whether the user is closing a form or window in which changes have been made, without having saved the changes.
You can also use the changed() function with a scrolling window to find out whether the line change script for the scrolling window is going to run.