Windows 8 HTML5/Javascript code sample that asks for a review of the app after 5 launches

example.js

// Ask for a review after 5 starts of the Application

// Variable to hold the number of time the app started
var startedCount = 0;
// Check if the 
variable was stored in the Roaming Settings before
var appData = Windows.Storage.ApplicationData.current;
var roamingSettings = appData.roamingSettings;
if (roamingSettings.values.hasKey("startedCount"))
{
    // If so, read it in the variable
    startedCount = roamingSettings.values["startedCount"];
}

// Increment the count by 1
startedCount++;
// And then save it in the Roaming Settings. Note that if the value pair was not
// created before, the method will create it automatically
roamingSettings.values["startedCount"] = startedCount;

// If the app was started 5 times
if (startedCount == 5)
{
    // Create a MessageDialog requesting a review
    var md = new Windows.UI.Popups.MessageDialog(
        "Thank you for using Grid App for a while now, would you like to review this app?",
        "Please review my app");

    // Build the 2 potential responses using the Commands collection
    md.commands.append(new Windows.UI.Popups.UICommand(
        "Yes", 
        function (command) {
            // Find the FamilyName of the app package
            var familyName = Windows.ApplicationModel.Package.current.id.familyName;
            // Navigate to the store Review Page for the Application
            var uri = new Windows.Foundation.Uri("ms-windows-store:REVIEW?PFN={0}", familyName);
            Windows.System.Launcher.launchUriAsync(uri);
        }));
    md.commands.append(new Windows.UI.Popups.UICommand(
        "No"));
                    
    // Set the command that will be invoked by default
    md.defaultCommandIndex = 0;
    // Set the command to be invoked when escape is pressed
    md.cancelCommandIndex = 1;

    // Display the MessageBox asyncronously.
    md.showAsync();
}