Appendix B. Silverlight and the Extensible Application Markup Language
What’s Silverlight? Silverlight is an implementation of Microsoft’s .NET Framework that has been scaled down and tuned to build good-looking, interactive, and responsive client applications. Silverlight includes the .NET Framework APIs needed for client-side application features and strips out APIs not well suited for restricted environments like the browser and Windows Phone. Silverlight application user interfaces are designed with the Extensible Application Markup Language (XAML) and its related Silverlight class libraries.
XAML was first introduced as part of the Windows Presentation Foundation. XAML excels as a user interface markup language, separating the user interface design from the code behind implementing an application’s business logic. XAML not only defines WPF and Silverlight UIs, but is one of the options when building WinRT applications for the upcoming Windows 8 operating system. If you’re coming from a web development background, you can think of XAML as similar to HTML, which you use to create UI for your web page. XAML is an XML document that represents the hierarchical structure of an application’s user interface.