3rd example explaining closures to Pat

closure3.js

var stopWatchBuilder = function() {

  var outerFunctionState = Date.now();
  var innerFunction = function() {
    console.log("Time difference: " + (Date.now() - outerFunctionState)/1000);
  }

  return innerFunction;
}

var timer = stopWatchBuilder();

// Next to no time at all from when we generateFunction1 and call it
timer();

// Artificial time delay
for (var i = 0; i < 1000000000; ++i) {}
for (var i = 0; i < 1000000000; ++i) {}
for (var i = 0; i < 1000000000; ++i) {}

// But when we call it later we get the difference of the current time
// and the outerFunctionState which is the time when we first generated
// the function
timer();

for (var i = 0; i < 1000000000; ++i) {}
for (var i = 0; i < 1000000000; ++i) {}

// Again!
timer();