What is the difference and importance

Question

what is the difference between JavaScript and PHP can we use the interchangeable if so which one is better?

Answer 1

ok thank you for your response

Answer 2

both have different usage.
javascript is client side language use to add interactivity to web pages.
while php is server side language use to add interactivity, handle database, dealing with session, cookies, handling security etc.
so both have different use and as a full stack developer you need to know both.