Javascript Array binarySearch(target, comparator)

/*/*  ww w.  j a v  a2s  .  c o  m*/
 target: the object to search for in the array
 comparator: (optional) a method for comparing the target object type
 return value: index of a matching item in the array if one exists, otherwise the bitwise complement of the index where the item belongs
 */
Array.prototype.binarySearch = function (target, comparator) {
    var l = 0,
        h = this.length - 1,
        m, comparison;
    comparator = comparator || function (a, b) {
            return (a < b ? -1 : (a > b ? 1 : 0)); /* default comparison method if one was not provided */
        };
    while (l <= h) {
        m = (l + h) >>> 1;
        comparison = comparator(this[m], target);
        if (comparison < 0) {
            l = m + 1;
        } else if (comparison > 0) {
            h = m - 1;
        } else {
            return m;
        }
    }
    return~l;
};