AutoTab without words getting cut off

I created a form that has 3 text fields to enter in a long description. I was able to find a script to autotab onto the next text field after a character limit is reached, but now words get cut off in the middle if the character limit is reached. Is there a way to automatically move a word to the next line if it gets cut off due to the character limit?

This is what it looks like now:

Line 1: "This is a long sentence to demonstr

Line 2: "ate."

I want it to act like this:

Line 1: "This is a long sentence to

Line 2: "demonstrate."