JavaScript storage using localstorage with Get, Set, Delete. Falls back to 30-day cookies if LocalStorage is not supported.

js-local-storage.js

// Usage:
cache.set('name', 'Radley');

alert( cache.get('name') ); // Displays "Radley"

cache.delete('name');

alert( cache.get('name') ); // Displays ""
// End of usage. Note that this code must go below the actual cache definition (below)


// --------------


// Caching mechanism
let cache = new function() {

  let date_now = new Date();
  let date_30days = new Date();
  date_30days.setTime( date_now.getTime() + (1000*60*60*24*30) ); // ms, s, m, h, d
  
  this.set = function( name, value ) {
    try {
      localStorage.setItem( name, value );
    } catch(e) {
      document.cookie = name + "=" + value + ";path=/;expires=" + date_30days.toGMTString();
    }
  };

  this.get = function( name ) {
    try {
      return localStorage.getItem( name );
    } catch(e) {
      let v = document.cookie.match('(^|;) ?' + name + '=([^;]*)(;|$)');
      return v ? v[2] : null;
    }
  };

  this.delete = function( name ) {
    try {
      localStorage.removeItem( name );
    } catch(e) {
      document.cookie = name + "=;path=/;expires=" + date_now.toGMTString();
    }
  };
};