Silverlight combines multiple technologies into a single development platform that enables you to select the right tools and the right programming language for your needs. Silverlight offers you the following features:
WPF and XAML. Silverlight includes Windows Presentation Foundation (WPF) technology, which greatly extends the elements in the browser for creating UI. WPF lets you create immersive graphics, animation, media, and other rich client features, extending browser-based UI beyond what is available with HTML alone. Extensible Application Markup Language (XAML) provides a declarative markup syntax for creating WPF elements.
See Creating User Interfaces with Silverlight for more information.
Extensions to JavaScript. Silverlight provides extensions to the universal browser scripting language that provide powerful control over the browser UI, including the ability to work with WPF elements.
See Silverlight 1.0 - Development with JavaScript for more information.
Cross-browser, cross-platform support. Silverlight runs the same on all popular browsers (on any platform). You can design and develop your application without having to worry about which browser or platform your users have.
See Creating and Deploying Silverlight Applications for more information.
Integration with existing applications. Silverlight integrates seamlessly with your existing JavaScript and ASP.NET AJAX code to complement functionality you have already created.
See Integrating Silverlight with ASP.NET Web Pages for more information.
Access to the .NET Framework programming model and to associated tools. You can create Silverlight-based applications using dynamic languages such as managed JScript and IronPython as well as languages such as C# and Visual Basic. You can use development tools such as Visual Studio to create Silverlight-based applications.
See Common Language Runtime and Base Class Library in Silverlight and Dynamic Languages in Silverlight 2 for more information.
LINQ. Silverlight includes language-integrated query (LINQ), which enables you to program data access using intuitive native syntax and strongly typed objects in .NET Framework languages.
See Parsing XML Data in Silverlight for more information.
If you already use ASP.NET, you can integrate Silverlight with the server and client capabilities of ASP.NET that you are familiar with. You can create server-based resources in ASP.NET and use the AJAX capabilities of ASP.NET to interact with server-based resources without interrupting the user.
Reference by :http://msdn.microsoft.com