"Silverlight 1.0 uses a retained graphics system (a canvas) that exposes the internal structure to the browser DOM. It has no scripting capabilities built into it, all the scripting support is actually done by the Javascript interpreter in the browser and all changes are done by talking to a Javascript object exposed by the hosted Silverlight surface. The scene definition is done using the XAML markup using a subset of the WPF primitives available in the full-blown WPF." (Miguel)