Really simple localStorage wrapper - depends on modernizr

local-storage.js

var storage = {
    _impl: null,

    // https://developer.mozilla.org/en-US/docs/Web/Guide/API/DOM/Storage
    implementationDummy: {
        getItem: function(sKey) {
            if (!sKey || !this.hasOwnProperty(sKey)) {
                return null;
            }
            return unescape(document.cookie.replace(new RegExp("(?:^|.*;\\s*)" + escape(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=\\s*((?:[^;](?!;))*[^;]?).*"), "$1"));
        },

        key: function(nKeyId) {
            return unescape(document.cookie.replace(/\s*\=(?:.(?!;))*$/, "").split(/\s*\=(?:[^;](?!;))*[^;]?;\s*/)[nKeyId]);
        },

        setItem: function(sKey, sValue) {
            if (!sKey) {
                return;
            }
            document.cookie = escape(sKey) + "=" + escape(sValue) + "; expires=Tue, 19 Jan 2038 03:14:07 GMT; path=/";
            this.length = document.cookie.match(/\=/g).length;
        },

        length: document.cookie.match(/\=/g).length,

        removeItem: function(sKey) {
            if (!sKey || !this.hasOwnProperty(sKey)) {
                return;
            }
            document.cookie = escape(sKey) + "=; expires=Thu, 01 Jan 1970 00:00:00 GMT; path=/";
            this.length--;
        },

        hasOwnProperty: function(sKey) {
            return (new RegExp("(?:^|;\\s*)" + escape(sKey).replace(/[\-\.\+\*]/g, "\\$&") + "\\s*\\=")).test(document.cookie);
        }
    },

    implementationReal: {
        getItem: function(key) {
            return localStorage.getItem(key);
        },

        setItem: function(key, value) {
            return localStorage.setItem(key, value);
        },

        removeItem: function(key) {
            return localStorage.removeItem(key);
        }
    },

    initialize: function() {
        if (Modernizr.localstorage) {
            this._impl = this.implementationReal;
        } else {
            this._impl = this.implementationDummy;
        }
    },

    get: function(key) {
        if (!this._impl) {
            this.initialize();
        }

        return JSON.parse(this._impl.getItem(key));
    },

    set: function(key, value) {
        if (!this._impl) {
            this.initialize();
        }

        return this._impl.setItem(key, JSON.stringify(value));
    },

    remove: function(key) {
        if (!this._impl) {
            this.initialize();
        }

        return this._impl.removeItem(key);
    }
};

// Initialize
storage.initialize();

// EXAMPLE 1: Simple Set / Get
storage.set('user.name', 'Joe Doe');
storage.set('user.age', 42);

// Get by Key
storage.get('user.name');
storage.get('user.age');


// EXAMPLE 2: Complex Set / Get

var user = { 
  name: "Joe Doe",
  age: 42,
  address: {
     stret: "35th Ave 2026",
     city: "New York",
     country: "United States of America"
  }
};

// Write user to storage
storage.set('user', user);

// Get user from storage
var tmp = storage.get('user');

// Get Key