My Gist

test.js

// Generated by JSIL v0.8.2 build 13182. See http://jsil.org/ for more information. 

'use strict';
var $asm00 = JSIL.GetAssembly("1dd27d7b, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null");
var $asm01 = JSIL.GetAssembly("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089");
var $asm02 = JSIL.GetAssembly("System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089");

/* Generated by JSIL v0.8.2 build 13182. See http://jsil.org/ for more information. */ 
'use strict';
var $asm00 = JSIL.DeclareAssembly("1dd27d7b, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null");

JSIL.SetEntryPoint($asm00, $asm00.TypeRef("Program"), "Main", JSIL.MethodSignature.Void);

/* class Program */ 

(function Program$Members () {
  var $, $thisType;
  var $T00 = function () {
    return ($T00 = JSIL.Memoize($asm00.Program_$lMain$gc__AnonStorey0)) ();
  };
  var $T01 = function () {
    return ($T01 = JSIL.Memoize($asm01.System.Object)) ();
  };
  var $T02 = function () {
    return ($T02 = JSIL.Memoize($asm01.System.Console)) ();
  };
  var $T03 = function () {
    return ($T03 = JSIL.Memoize($asm01.System.Action)) ();
  };

  function Program_Main () {
    var $lMain$gc__AnonStorey = new ($T00())();
    var document = JSIL.GlobalNamespace.document;
    var window = JSIL.GlobalNamespace.window;
    var canvas = document.createElement("canvas");
    var arg_E5_0 = $lMain$gc__AnonStorey;
    arg_E5_0.ctx = canvas.getContext("2d");
    var body = document.getElementsByTagName("body")[0];
    $T02().WriteLine("Hello JSIL World!");
    body.appendChild(canvas);
    window.setInterval($T03().New($lMain$gc__AnonStorey, $T00().prototype.$l$gm__0, function () { return JSIL.GetMethodInfo($asm00.Program_$lMain$gc__AnonStorey0, "$l$gm__0", JSIL.MethodSignature.Void, false); }), 25);
  };

  function Program_Redraw (ctx) {
    $thisType.x = ((($thisType.x | 0) + 2) | 0);
    ctx.clearRect(0, 0, 300, 300);
    ctx.fillStyle = "red";
    ctx.fillRect($thisType.x, $thisType.y, 20, 20);
  };

  JSIL.MakeStaticClass("Program", true, [], function ($interfaceBuilder) {
    $ = $interfaceBuilder;

    $.Method({Static:true , Public:true }, "Main", 
      JSIL.MethodSignature.Void, 
      Program_Main
    );

    $.Method({Static:true , Public:true }, "Redraw", 
      JSIL.MethodSignature.Action($.Object), 
      Program_Redraw
    )
      .Parameter(0, "ctx", function (_) {
          _.Attribute($asm02.TypeRef("System.Runtime.CompilerServices.DynamicAttribute"))
        });

    $.Field({Static:true , Public:true }, "x", $.Int32, 10); 
    $.Field({Static:true , Public:true }, "y", $.Int32, 20); 
    function Program__cctor () {
      $thisType.x = 10;
      $thisType.y = 20;
    };


    $.Method({Static:true , Public:false}, ".cctor", 
      JSIL.MethodSignature.Void, 
      Program__cctor
    );

    return function (newThisType) { $thisType = newThisType; }; 
  });

})();

/* class Program+<Main>c__AnonStorey0 */ 

(function $lMain$gc__AnonStorey0$Members () {
  var $, $thisType;
  var $T00 = function () {
    return ($T00 = JSIL.Memoize($asm00.Program)) ();
  };

  function $lMain$gc__AnonStorey0__ctor () {
  };

  function $lMain$gc__AnonStorey0_$l$gm__0 () {
    $T00().Redraw(this.ctx);
  };

  JSIL.MakeType({
      BaseType: $asm01.TypeRef("System.Object"), 
      Name: "Program+<Main>c__AnonStorey0", 
      IsPublic: false, 
      IsReferenceType: true, 
      MaximumConstructorArguments: 0, 
    }, function ($interfaceBuilder) {
    $ = $interfaceBuilder;

    $.Method({Static:false, Public:true }, ".ctor", 
      JSIL.MethodSignature.Void, 
      $lMain$gc__AnonStorey0__ctor
    );

    $.Method({Static:false, Public:false}, "$l$gm__0", 
      JSIL.MethodSignature.Void, 
      $lMain$gc__AnonStorey0_$l$gm__0
    );

    $.Field({Static:false, Public:false}, "ctx", $.Object)
      .Attribute($asm02.TypeRef("System.Runtime.CompilerServices.DynamicAttribute")); 
    return function (newThisType) { $thisType = newThisType; }; 
  })
    .Attribute($asm01.TypeRef("System.Runtime.CompilerServices.CompilerGeneratedAttribute"));

})();

tryjsil.cs

using System;
using JSIL;
using JSIL.Meta;

public static class Program {
  public static int x = 10;
  public static int y = 20;
  
  public static void Main () {
    dynamic document = Builtins.Global["document"];
    dynamic window = Builtins.Global["window"];
    
    var canvas = document.createElement("canvas");
    var ctx = canvas.getContext("2d");
    var body = document.getElementsByTagName("body")[0];

    Console.WriteLine("Hello JSIL World!");

    body.appendChild(canvas);
    
    window.setInterval((Action)(() => {
      Redraw(ctx);
    }), 25);
  }
  
  public static void Redraw (dynamic ctx) {
    x += 2;
    
    ctx.clearRect(0, 0, 300, 300);
    
    ctx.fillStyle = "red";
    ctx.fillRect(x, y, 20, 20);
  }
}