Reloading

Question

Coupd i know why the page reload when i click the submit button and why if i write return false it doesn’t?
Plz i wanna understand it logically

Answer 1

Please show your code.

Answer 2

https://code.sololearn.com/Wo3yb8A3HE2P/?ref=app
for example in this code i do not put it and there is no a problem
but in another one i have