how to setItem and getItem in javascript in localStorage

function set(){
var sendJSON = JSON.stringify(allMovie);

function get(){
var getJSON = localStorage.getItem('allMovie');
if (getJSON){
allMovie = JSON.parse(getJSON)



//localStorage is an object, so values are stored by key name
//data from localStorage is always stored in strings
//usually the values at each key are stringified objects in JSON format, therefore we must parse them
var data = JSON.parse(localStorage.getItem("key name"));//make sure the "key name" exists in the localStorage

var KeyName = window.localStorage.key(index);