Tip Calculator with Grid and JS

What are you most proud of, and what would you do differently next time?

I'm proud that I was able to figure out how to grab data from the form without a submit button.

What challenges did you encounter, and how did you overcome them?

Allowing for the custom tip. Once I enabled that functionality, using the static tip amounts resulted in getting NaN as the tip and total amounts.

What specific areas of your project would you like help with?

Any constructive criticism is welcome!