Why is the code showing error for localStorage used

Question

https://code.sololearn.com/WEdYcEmV9FWo/?ref=app

Answer 1

If you want to use web browser localstorage on your mobile device you should use the Sololearn website via your mobile browser. It shouldn't be a problem for most mobile browsers.

As far as your other question these should help.
https://code.sololearn.com/WcdoF4PGPyDC/#html
https://code.sololearn.com/WKn8Mq5DU052/#js

Answer 2

localStorage is not supported in sololearn playground.