responsive tip calculator using html and css

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

create custom field for user to enter percentage

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

how to check if the text enter is number while preserving last character as percentage sign before checking type of text remove the percentage sign. after checking type of text add the percentage sign

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

how to simplify the js code