Tip calculator app using HTML, CSS, and JavaScript

Hi y'all..

I learned so much about JavaScript through this challenge. I learned how to code about a year ago but I wasn't consistent with my practice. While solving this challenge I realized how much I've forgotten and that I lacked practical skills.

For JS, I have these questions, if I may...

• Overall, I believe there are functions that would make my coding more concise and less of so many repeated ones. If you have any advice, I welcome anything!
• Can't seem to come up with how to '.toFixed(2)' bill amount. I want it where after you put amount and click elsewhere, it shows you rounded amount with 2 decimal places.
• Couldn't figure out how to make results change according to the change of 'bill' and 'number of people', so I had to make it undo the 'tip selector' button as you change value of them so that after that you can 're-type' to see the results. Otherwise the previous result will remain with different button selected, if this makes sense.

• How do I eliminated the arrow buttons that are automatically inside 'input[type=number]'? I tried '-moz-appearance: textfield;' and such, but it keeps getting reported as 'problems'.

I was really excited to solve this challenge, as I have only focused on HTML and CSS so far. I want to get better at JS quickly so any advice will help! :) Cheers!