JSIL is a compiler that transforms .NET applications and libraries
from their native executable format - CIL bytecode - into
standards-compliant, cross-browser JavaScript. You can take this
JavaScript and run it in a web browser or any other modern JavaScript
runtime. Unlike other cross-compiler tools targeting JavaScript, JSIL
produces readable, easy-to-debug JavaScript that resembles the code a
developer might write by hand, while still maintaining the behavior and
structure of the original .NET code.
Demo