store data in browser javascript

// localStorage for objects, arrays or any data type
var obj = {
	firstName: "Bob",
    lastName: "Jeff",
    age: 13
}
localStorage.setItem("itemname", JSON.stringify(obj)); // Save the obj as string
var item = JSON.parse(localStorage.getItem("itemname")); 
// ^^ Parse string then set `item` as the objlocalStorage.setItem("user_name", "Bob");

document.body.addEventListener("click", function(){
  alert(localStorage.getItem("user_name"))
});var testObject = { 'one': 1, 'two': 2, 'three': 3 };

// Put the object into storage
localStorage.setItem('testObject', JSON.stringify(testObject));

// Retrieve the object from storage
var retrievedObject = localStorage.getItem('testObject');

console.log('retrievedObject: ', JSON.parse(retrievedObject));