If you can't create new file and put the function there as suggested in the answer one other way is reading abc2.asp using FileSystemObject, extract the function as raw string and use Execute() method of VBScript to make it part of the context in abc1.asp as well. Dirty but it would work. If interested let me know and I'll come with sample code, however note it's NOT good practice.
Create a third file, maybe called functions.asp - put your functions in that then include it in abc1.asp and abc2.asp by means of an include file statement - see below
Execute()method of VBScript to make it part of the context in abc1.asp as well. Dirty but it would work. If interested let me know and I'll come with sample code, however note it's NOT good practice.