restoring application data array after refresh HTML 5 Localstorage

I think you're going by this wrong. You cant expect saved variable to exist after page refresh can you? You have to check if the data from localStorage is null or not and base your code on that :

window.onload = function () {
    //get data from localStorage
    var saved = handlers.getPresentationData();
    //check if its null / undefined
    if ([null, undefined].indexOf(saved) === -1) {
        //its not null/undefined - data exists!
        console.log("Data exists. Here's the data : ", saved);
        //set your "app" to data from localStorage
        app = saved;

        //Do whatever you want with app - Im choosing to ask for deleting
        if (confirm("Clear locally Stored data?")) {
            handlers.clearAppData();
        }

    } else {
        //data DOES NOT exist in localStorage
        console.log("Data does not exist, save to localStorage");
        //So, save it in localStorage. Refresh this page now.
        handlers.savePresentationData();
    }

};

Oh, and you need three handlers,

• Save
• Get
• Clear

like this :

var handlers = {
    savePresentationData: function () {
        // Place the app object into storage
        localStorage.setItem("app", JSON.stringify(app));
    },
    getPresentationData: function () {
        // Retrieves the object app from HTML 5 local storage
        var retrievedObject = localStorage.getItem("app");
        var savedData = JSON.parse(retrievedObject);
        return savedData;
    },
    clearAppData: function (event) {
        localStorage.clear();
        return false;
    }
};

Demo : http://jsbin.com/icafac/1/edit

Things I've removed :

• Passing event argument to function in handlers.
• saved variable which was used for true/false is now used for saving data from localStorage

Hope this helps!

You need one handler to load your data, and one to save it. Try loading the data, and pass a default value. If the load fails, the function will return the defaults you've set:

var app = { .. values .. },
handlers = {
    loadPresentatioData: function (defaults) {
        /**
         * Retrieve stored value
         */
        var loaded = localStorage.getItem('app');

        /**
         * Use defaults if no stogare is found
         */
        if (!loaded) {
            localStorage.setItem('app',JSON.stringify(defaults));
            loaded = localStorage.getItem('app');
        }

        /**
         * Prevent errors if the parsing goes wrong
         * Defaults to original app value
         */
        try {
            loaded = JSON.parse(loaded);
        }
        catch (e) {
            loaded = defaults;
        }

        return loaded;
    },
    savePresentationData: function (data) {
        var serialized;

        try {
            serialized = JSON.stringify(data);
            localStorage.setItem('app',serialized);
        }
        catch (e) {
            // Something went wrong
        }
    }
};