(function(window, document, undefined) {
  window.onload = init;
  function init() {
    var c = document.getElementById("mapCanvas");
    c.width = 960;
    c.height = 540;
    var ctx = c.getContext("2d");
    ctx.fillStyle = "#FF0000";
    for(x=0; x<100; x+2){
      for(y=0; y< 100; y+2){
        ctx.fillRect(x, y, 1, 1);
      }
    }
  }
})(window, document, undefined);

@@ -236,67 +236,8 @@
 0%22;%0A
-    for(x=0; x%3C100; x+2)%7B%0A      for(y=0; y%3C 100; y+2)%7B%0A    
     
@@ -259,29 +259,15 @@
  y, 
-1, 1
+2, 2
 );%0A
-      %7D%0A    %7D%0A
   %7D%0A

Update script.js