Tip Calculator app

A few comments about this one.

1. I found the design size to be way too small, even usability was difficult so I kept it larger.
2. I had some odd quirks with the JS, sometimes it seemed to work, sometimes it didn't.
3. Found some cool useful tricks dealing with number input fields so that was handy.

I don't have any real questions, this was a lot more difficult than I expected it to be considering I have done calculators before.