local storage for chrome extension

1chrome.storage.local.set({key: value}, function() {  console.log('Value is set to ' + value);});chrome.storage.local.get(['key'], function(result) {  console.log('Value currently is ' + result.key);});

1var valeur=localStorage.getItem(clef);  //récupérer la valeur
2localStorage.setItem(clef,valeur);  //donner une nouvelle valeur
3localStorage.removeItem(clef);  //supprimer l'item
4var clef=localStorage.key(n);  //récupérer la clef du n item.
5localStorage.clear();  //vider localStorage
6localStorage.length();  //le nombre de clef de localStorage