SOURCE

localStorage.setItem("a","linyi");
console.info(localStorage.getItem("a"));
console.info(localStorage.length);
console.info(localStorage.key(2));
function forEachKey(callback) {
  for (var i = 0; i < localStorage.length; i++) {
    callback(localStorage.getItem(localStorage.key(i)));
  }
}
forEachKey(console.info)