Build RIA with Visual Studio, Angular JS and TypeScript
Silverlight is by far the best tool to build Rich Internet Application (RIA), but Microsoft is killing it, and all browsers have ended or are ending the support for Silverlight.
A good alternative is JavaScript-based web app. The most productive environment is Visual Studio + Angular JS + TypeScript (a superset of JavaScript). A good starting point is the ASP.NET Core + Angular 2 template for Visual Studio.
Client-side JavaScript app has little protection of intellectual property. Letting comments requiring IP protection on the server-side can address this issue to a certain degree