How to make submit button active only if all form fields are filled?

Question

JavaScript

Good afternoon dear community.
There is a form with an inactive submit button. The question is how to make it active, but only on condition that all form fields are filled out?

Answer 1

1. Write a check, if the check passes then remove the class that is disabled
2. Use AngularJs,
3. google on this topic - https://www.google.ru/search?q=javascript+form+val...