gistfile1.js

function global_test() {
  global.test = function (){
    var start = Date.now();
    var a = -100000000;
    for (var i = 0; i < 1000; i++) {
      for (var j = 0; j < 1000; j++) {
        a += i + j;
      }
    }
    var end = Date.now();
    return (end - start);
  };

  var total = 0;
  var N = 1000;
  for (var i = 0; i < N; i++) total += global.test();
  console.log("global test: %s ms per test", total/N);
}

function local_test() {
  var test = function (){
    var start = Date.now();
    var a = -100000000;
    for (var i = 0; i < 1000; i++) {
      for (var j = 0; j < 1000; j++) {
        a += i + j;
      }
    }
    var end = Date.now();
    return (end - start);
  }

  var total = 0;
  var N = 1000;
  for (var i = 0; i < N; i++) total += test();
  console.log("local_test: %s ms per test", total/N);
}

local_test();
global_test();