Silverlight is a Microsoft plug-in which provides support for Rich Internet Applications (RIAs). Silverlight enables graphical and animation displays with multimedia and interactivity built in. This is comparable to the functionality provided by Flash. Similarly to java, Silverlight runs within a sandbox to cater for security. The programming model is extremely flexible supporting multiple languages including VB, C#, Python, and Ruby. Silverlight integrates with existing AJAX style Web applications.
The Silverlight plug-in uses Extensible Application Mark-up Language (XAML) to render user interfaces within a browser. Silverlight can run on Explorer 6+, Firefox 1.5+ & 2 and Safari 2 on the latest Windows (XP, Server 2003 and Vista) and Mac OS X platforms. The plug-in is capable of playing different media formats (VC-1, WMA and MP3). The plug-in does not require the .NET Framework or Windows Media Player to be present on the client.