A design question. If all what you wanted to do is to strip the () at the beginning (or even couple of places), why not just have two (or more) textareas.

That would be much clearer, both the user interface and code.

You don't want your user to enter something that follows certain syntax. Whenever you can, try to make their lifes easier. That's the purpose of having GUI.

When you write programs, try to be lazy and straight.