Nothing special....Either
- A user specified point that is snapped to the line. Once placed it splits the line in two. Error alert if it does not land on a line
- A user specified line intersecting the line to split. Click once to start the splitting line, drag across a line to be split, click second time to stop. Error alert if it does not cross a line to be split.
UPDATE: Forgot to thank you for your reply....very appreciated.