function createCounter() {
    var counter = 0;

    var myFunction = function() {
      counter = counter + 1;
      return counter;
    }

    return myFunction;
 }

 var increment = createCounter();
 var c1 = increment();
 var c2 = increment();
 var c3 = increment();
 console.log(c1, c2, c3); // 1 2 3