Why is the page blank after you clicked the button?

Question

https://code.sololearn.com/Wx7l3siVMy6l/?ref=app

Answer 1

Buttons in forms cause the form to redirect/submit to its action attribute url... Switch <form> to <div> perhaps?

Answer 2

I prefer @ValentinHacker's answer because I don't think you need a form, but you can also cancel the submit by returning false (this tells Javascript the form failed the 'validator function')

20: return false; // 'validator' says stop

Answer 3

oh yes thank you