Script trigger to make sure user enters data
I have a field on a layout. I want to set a script trigger that evaluates if data is in a field and if so, will not allow a user to clear the field. Rather, a user can change the value or leave the current value. If the field was blank to begin with, nothing will trigger. If the field is blank and a user enters data and clears it, nothing should trigger. For the last example I think I may have to use a popup layout where records can't commit until the window is closed and a script runs (using the web viewer trick (web viewer blocks a user from clicking outside a field to commit the record)).
Is this possible?