Do you guys have any ideas to improve my web app ?

Question

Kg to grams application
https://code.sololearn.com/WhiTGd7u8YcI/?ref=app

Answer 1

use Maximum Length in input

Answer 2

sprinkle some AngularJS magic on it

remove convert button and handle input as it entered with angular

Answer 3

is the conversion supposed to work? because when i hit the convert button it take me to an error page