In Windows 8 Apps with HTML5 and JavaScript Unleashed, author Stephen Walther covers everything you need to build, test, and distribute outstanding Windows 8 software with JavaScript and HTML5. Walther clearly demonstrates the unique advantages Windows 8 offers to web developers. He guides you through using Microsoft’s new WinJS library to develop apps for Microsoft’s brand-new version of Windows--you learn how to use JavaScript templates, controls, and data binding. You’ll find in-depth coverage of everything from displaying data with a ListView control to supporting SkyDrive cloud storage, creating games to using IndexedDB and HTML5 forms.

Windows 8 Apps with HTML5 and JavaScript Unleashed

By Stephen Walther Published Nov 20, 2012 by Sams, Part of the Unleashed series. Copyright 2013. Sample Chapter is provided courtesy of Sams Publishing. Book Page:

In This Chapter

  • What Is a Windows Store App?
  • Creating Your First Windows Store App
  • Elements of a Windows Store App
  • Building Windows Store Apps with Visual Studio
  • Debugging a Windows Store App
  • Publishing to the Windows Store

In this chapter, I introduce you to the basics of building Windows Store apps. I start off by explaining how a Windows Store app differs from a traditional Windows desktop application. You learn what makes a Windows Store app a Windows Store app.

Feeling fearless and bold, and hoping that you too feel fearless and bold, I next guide you through building your first Windows Store app. You learn how to take advantage of the features of Microsoft Visual Studio 2012 to build, run, and debug a Windows Store app.

Next, we dive into a discussion of the fundamental elements of a Windows Store app. You learn how a Windows Store app is forged out of HTML5, JavaScript, the Windows Library for JavaScript, and the Windows Runtime.

Finally, we get to the money part. I explain how you can publish your Windows Store app to the Windows Store and start collecting those dollars.

What Is a Windows Store App?

I can still remember the first time that I used an iPhone. When you scroll the screen on an iPhone, the screen actually bounces! And when you add an email to the trash, the email gets sucked into the trashcan! It’s as if there is a little universe inside an iPhone and it follows our physical laws.

For some reason-that I have not explored and that I do not completely understand-this illusion that there is a second universe inside my iPhone makes me happy. It makes interacting with an iPhone fun.

Now we come to Windows. Except for the dancing card thing in Windows Solitaire, I can’t think of anything in Windows that has ever created this same sense of fun. I can’t remember the last time that Windows made me laugh or brought me joy.

With Windows Store apps, Microsoft has finally acknowledged that user experience matters-in a big way. The heart of Windows Store apps is a set of user experience principles named the Microsoft design style principles. By embracing the Microsoft design style principles, you can create Windows Store apps that seem more alive and that are a pleasure to use.

Microsoft Design Style Principles

The Microsoft design style principles is a set of user experience design principles developed by Microsoft in the context of building the Windows Phone, Xbox Live, and the (now defunct) Zune. You also can see the Microsoft design principles applied to Microsoft websites such as Microsoft SkyDrive and the Windows Azure Portal. Get ready. Here they are:

1. Show pride in craftsmanship.

  • Devote time and energy to small things that are seen often by many.
  • Engineer the experience to be complete and polished at every stage.

2. Do more with less.

  • Solve for distractions, not discoverability. Let people be immersed in what they love and they will explore the rest.
  • Create a clean and purposeful experience by leaving only the most relevant elements on screen so people can be immersed in the content.

3. Be fast and fluid.

  • Let people interact directly with content, and respond to actions quickly with matching energy.
  • Bring life to the experience, create a sense of continuity and tell a story through meaningful use of motion.

4. Be authentically digital.

  • Take full advantage of the digital medium. Remove physical boundaries to create experiences that are more efficient and effortless than reality.
  • Embrace the fact that we are pixels on a screen. Design with bold, vibrant and crisp colors and images that go beyond the limits of real world material.

5. Win as one.

  • Leverage the ecosystem and work together with other apps, devices and the system to complete scenarios for people.
  • Fit into the UI model to reduce redundancy. Take advantage of what people already know to provide a sense of familiarity, control, and confidence.


The Microsoft design style principles were originally known as Metro design principles. This list of Microsoft design style principles was taken from and

When I first read these principles, my initial reaction was that they seemed overly abstract and squishy. Exactly the type of principles which would be created by beret wearing user experience guys.

But then, when I saw how the principles were applied in practice-when building actual Windows Store apps-I started to develop a better appreciation for these principles.

Take the “Do more with less” design principle. One of the distinctive features of a Windows Store app is the lack of chrome. Ironically, a Windows Store app is a Windows app without the Window. Windows Store apps are full screen apps.

This lack of chrome makes it easier to concentrate on the content of the application. For example, Windows 8 includes two versions of Internet Explorer: a desktop version and a full-throated Windows 8 version which follows the Microsoft design style principles.

I really prefer using the Windows 8 version of Internet Explorer over the desktop version. When using the Windows 8 version, all you see is the web page which is the point of the application in the first place.

Or consider the “Be fast and fluid” principle. The reason that I like interacting with my iPhone so much is the illusion of motion and this illusion is created by the judicious use of animations: On an iPhone, objects bounce and wobble.

When building a Windows Store app, you are encouraged to take advantage of animations. For example, if you use the standard ListView control-which we discuss in detail later in this book-then you get animations when you add or remove items. When you add an item to a ListView, it not only appears, it glides into place. When you remove an item, it doesn’t just disappear, items above and below it collapse into place.


There is a technical word for when a computer app imitates physical reality. The word is skeuomorphism.

Common Features of Windows Store Apps

Windows Store apps are applications which follow the Microsoft design style principles. Furthermore, Windows Store apps are designed to run on the Windows 8 or Windows RT operating system.

All Windows Store apps have a common set of features. Let me explain these features by pointing them out in the context of the Windows 8 version of Internet Explorer.

Support for Keyboard, Mouse, Touch, and Stylus

One of the most distinctive characteristics of a Windows Store app is its over-sized tiles and buttons and generous use of whitespace. All of this UI roominess makes Windows Store apps friendly to fat fingers.

Windows Store apps are designed to work equally well when used on a touch-only tablet and when used on a desktop computer with a keyboard and mouse. Windows Store apps are designed to be gropeable.

The nice thing about how Windows 8 works is that you don’t need to put a lot of thought into supporting touch as a developer. As long as you stick with the standard WinJS controls, you get both keyboard and touch support for free.

Using the App Bar and Nav Bar

Figure 1.1 contains a screenshot of the Windows 8 version of Internet Explorer with the home page of the New York Times open. Notice that the only thing that you see is the content of the New York Times. No toolbars, no buttons, no status bars.

Figure 1.1. Windows 8 Internet Explorer

In a Windows Store app, you hide all of your commands in the app bar. The app bar appears only when you swipe from the bottom or top of the screen or you right-click the screen.

The app bar for Internet Explorer includes the address bar and buttons such as the back button and refresh button (see Figure 1.2).

Figure 1.2. Using the app bar and nav bar

Notice in Figure 1.2 that there is another bar at the top of the screen. This bar is called the nav bar and you use it to navigate. In the case of Internet Explorer, the nav bar contains thumbnails of all of your open browser tabs.

Using Charms

If you swipe from the right edge of the screen or mouse to either of the right corners or press the keyboard combination Win+c, then the charms are revealed (see Figure 1.3).

Figure 1.3. Viewing charms

Here’s a list of the standard charms:

  • Search-Enables you to search content in the current app and other apps.
  • Share-Enables you to share content in the current app with other apps.
  • Start-Navigates you to the Start screen.
  • Devices-Enables you to connect to a device.
  • Settings-Enables you to configure both app settings and system settings.

These charms provide you with standard locations to place common application functionality. For example, all Windows Store app settings should appear in the Settings charm (see Figure 1.4). This makes it much easier for users to find your settings.

Figure 1.4. The Settings charm

When you are building a Windows Store app, you don’t build your own settings menu. Instead, you extend the Settings charm with your custom app settings. I discuss the details of doing this in Chapter 6, “Menus and Flyouts.”

Full Screen, Snapped, and Filled

A Windows Store app can be in three different view states: Full screen, snapped, and filled. The default state is full screen-the app takes over all of the available screen real estate.

You can switch an app between the different view states by pressing the keyboard combination Win+. (period) or by swiping from the top-edge to the left edge of the screen or by mousing to the top-left corner and dragging down.


You can switch an app to snapped state only on a Windows device with a horizontal resolution of 1,366 pixels or higher. Otherwise, there is not enough screen real estate to see more than one app at a time.

Figure 1.5 shows two Windows 8 apps on the screen at one time. The Weather app is in a snapped state and the Internet Explorer app is in a filled state. A snapped app always has a horizontal resolution of 320 pixels. The filled app takes up the remainder of the screen real estate.

Figure 1.5. Snapped and filled apps

When building Windows Store apps, you need to design the app so it works in full screen, snapped, or filled state. At any moment, the horizontal resolution of your app could be dramatically changed. I discuss how to handle switching between different view states in Chapter 9, “App Events and States.”

Closing a Windows Store App

Now close a Windows Store app by moving your cursor over the x at the top-right of the screen. Ha! Tricked You! There is no close button in a Windows Store app because there is no chrome.


Even though it is not obvious how to close a Windows Store app, it is possible. You can close a Windows Store app by swiping down from the top of the screen to the very bottom of the screen or pressing the keyboard combination ALT+F4.

When interacting with Windows Store apps, there is no obvious way to close an app. This is intentional. Instead of closing a Windows Store app, you are encouraged to simply switch to another running app (by swiping from the left edge of the screen) or launch a new app (by selecting a new app from the Start screen).

When you design a Windows Store app, you must design the app with the knowledge that a user might switch back and forth to your running app at any time. In Chapter 9, I discuss how you can gracefully resume an app after it has been suspended.

Creating Your First Windows Store App

Let’s be fearless. In this section, I guide you through building your first Windows Store app. Doing a Hello World app would be predictable and boring. Therefore, I suggest that we do something a little more advanced.

I’ll show you how you can create an app which enables you to take pictures. When you click the Take Picture command in the app bar, you can take a picture, and then the picture is displayed in the app (see Figure 1.6, which shows a picture of my dog Rover).

Figure 1.6. Your first Windows Store app


The code for the completed app can be found in the Chapter1 folder with the name App1.

Creating the Visual Studio Project

The first step is to create the Microsoft Visual Studio Project. I used Visual Studio 2012 to create almost all of the code samples for this book. In most cases, I used the free version of Visual Studio-Visual Studio 2012 Express for Windows 8-which you can download from


In chapters in which I created a web service project, I used Visual Studio Professional 2012 because I needed to create both a Windows Store app and an ASP.NET project in the same solution.


You can create Windows Store apps with either Microsoft Visual Studio 2012 or Microsoft Blend. If you need to release to the Windows Store, then I recommend using Microsoft Visual Studio 2012.

In order to build Windows Store apps, you must use Visual Studio on Windows 8. If you don’t have a dedicated Windows 8 computer, you can use a virtual machine running Windows 8 such as VMware Player.

Go ahead and launch Visual Studio. Next, select the menu option File, New Project. On the left-side of the New Project dialog, select JavaScript and select the Blank App project template. Enter the name App1 for your project and click the OK button (see Figure 1.7).

Figure 1.7. Using the Visual Studio New Project dialog

After you create your project, you can see all of the files for your project in the Solution Explorer window (Figure 1.8). When you create a new Windows Store app, you get a default.html file (in the root of your project), a default.js file (in the js folder), and a default.css file (in the css folder). These three files are the starting point for your app.

Figure 1.8. Windows Store app default files.

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