Windows 8 Metro Interface - Is it IE10?

Question

I've started playing with Windows 8 recently, and (as a web developer) I'm using JavaScript to build my Metro-style app.

I've learned how to use the debugging tools in VS Express 2012... but it occurs to me that the wrapping WebView (or whatever it's called) could simply be a stripped-down IE10.

I've never heard an explanation for what the HTML/JS engine is in this environment. Does anyone know what is happening under the hood?

Answer 1

This is correct. The rendering of Windows 8 WinRT apps built with XAML is handled by XAML and the ones being built using JS/HTML/CSS are rendering using an IE10's HTML rendering engine and IE10's JavaScript engine.

This is the main reason why IE10 is the only browser that currently implements CSS3 grid layout.

For debugging information on Windows Store Apps written using JavaScript/HTML/CSS:

There is a runtime DOM inspector provided by VS, there is Expression Blend where you can also run the app and there is the native VS debugger. However there is no tool like the IE10 developer tools. The intellitrace should give you enough networking information needed for debugging.

Answer 2

If you look in the Details tab of your Task Manager while you have a Windows 8 HTML/JS app running, you'll see a process called WWAHost.exe. That process is hosting the Trident (HTML/CSS) and Chakra (JavaScript) engines and running the app. The IE10 browser on your machine uses the same engine. There are a few differences between the way apps behave versus websites, however, and you can see those here.