Why localStorage doesn't work?

Question

Why localStorage.setItem() doesn't work?

Answer 1

It works now. I wrote localStorage.setItem('2','4')
The first parameter can not be a text string. I've removed quotes and it's working:
localStorage.setItem(2,'4')

Answer 2

//It works on browser, maybe your source code contains errors

Answer 3

//LocalStorage is not supported here on sololearn
https://www.sololearn.com/discuss/1199130/?ref=app

Answer 4

But I tried to create a html file and opened it in the browser and it does not work either.