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5. document.DOMContentLoaded fires. You can use this to do further initialization specifically related
to the DOM, if desired (not common).
6. Windows.UI.WebUI.WebUIApplication.onactivated fires. This is typically where you’ll do all
your startup work, instantiate WinJS and custom controls, initialize state, and so on.
7. The splash screen is hidden once the activated event handler returns (unless the app has
requested a deferral as discussed later in the “Activation Deferrals” section).
8. body.onload fires. This is typically not used in Windows Store apps, though it might be utilized
by imported code or third party libraries.
What’s also very different is that an app can again be activated for many different purposes, such as
contracts and associations, even while it’s already running. As we’ll see in later chapters, the specific
page that gets loaded (step 3) can vary by contract, and if a particular page is already running it will
receive only the Windows.UI.WebUI.WebUIApplication.onactivated event and not the others.
For the time being, though, let’s concentrate on how we work with this core launch process, and
because you’ll generally do your initialization work within the activated event, let’s examine that
structure more closely.
Sidebar: File Encoding for Best Startup Performance
To optimize bytecode generation when parsing HTML, CSS, and JavaScript, the Windows Store
requires that all .html, .css, and .js files are saved with Unicode UTF-8 encoding. This is the default
for all files created in Visual Studio or Blend. If you’re importing assets from other sources, check
this encoding: in Visual Studio’s File Save As dialog (Blend doesn’t have this at present), select
Save with Encoding and set that to Unicode (UTF-8 with signature) – Codepage 65001. The
Windows App Certification Kit will issue warnings if it encounters files without this encoding.
Along these same lines, minification of JavaScript isn’t particularly important for Windows
Store apps. Because an app package is downloaded from the Windows Store as a unit and often
contains other assets that are much larger than your code files, minification won’t make much
difference there. Once the package is installed, bytecode generation means that the package’s
JavaScript has already been processed and optimized, so minification won’t have any additional
performance impact.
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