QuickSort In Place (in JavaScript)

quicksort.js

// quicksort using new arrays is easy, but surprisingly, there weren't too many examples
// in javascript of in-place quick sort...

// the outer function is simply just a wrapper that copies the original array;
// you can just use lines 12-37 if preserving the original array isn't important

function quickSortInPlace(unsortedArray) {

  var unsorted = unsortedArray.slice();    // copy the original array

    // lb, rb - left bound, right bound
  function qSort(unsorted, lb, rb) {
    if(typeof lb === 'undefined') { lb = 0; }
    if(typeof rb === 'undefined') { rb = unsorted.length-1; }

    if(lb < rb) {
      var pivot = unsorted[Math.floor((lb+rb)/2)];
      var l = lb, r = rb;       // index variables that travel from either end
      var tmpSwap;

        // what some people call the partitioning
      while(l < r) {
        while(unsorted[l] < pivot) { l++; }
        while(pivot < unsorted[r]) { r--; }
        if(l <= r) {
          tmpSwap = unsorted[l];
          unsorted[l] = unsorted[r];
          unsorted[r] = tmpSwap;
          l++;
          r--;
        }
      }
  
      qSort(unsorted, lb, r);
      qSort(unsorted, l, rb);
    }
  }

  qSort(unsorted);
  return unsorted;
}

Please instantiate qSort in global scope, and then simply call it using parameters from quickSortInPlace's local scope.