Vistascript is a scripting development environment and runtime for WinFx. The developer includes a winform designer, class and file browsers, interactive debugger and compiler. The runtime interpreter supports XMPP, JSON, REST and SOAP protocols. The Vistascript language is modelled after the Javascript 2.0 proposal with extensions such as Smalltalk block closures. Vistascript is designed for building Ajax style applications on Windows Vista.