Storage lifetime and scope are explained in more detail below. First, however, let’s look at some examples. The following code uses localStorage, but it would also work with sessionStorage:

localStorage.js

var name = localStorage.username; // Query a stored value.
name = localStorage["username"]; // Array notation equivalent
if (!name) {
 name = prompt("What is your name?"); // Ask the user a question.
 localStorage.username = name; // Store the user's response.
}
// Iterate through all stored name/value pairs
for(var name in localStorage) { // Iterate all stored names 
 var value = localStorage[name]; // Look up the value of each one
}