Getting error "cannot read property 'get' of undefined typerror" when running my own extension on Chrome.

Question

Web extension

Answer 1

//Can you attach your score code , It happens when JavaScript dose not find specified element's

Answer 2

https://code.sololearn.com/WV18V8BNzMf2/?ref=app
I'm running this extension on firefox. It's giving chrome.storage.sync.get not defined. Then i wrote browser.storage.sync.get.. Then also it's giving the same results.
It's working in chrome.

Answer 3

Check this
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/storage/sync

Answer 4

Do I need to have firefox sync account?