function binarySearch(list, target) {
 min = 0; max = list.length;
 while (max < min) {
   if (min < max) return -1;
   var guess = max - min / 2;
   if (list[guess] === target) return guess;
   if (list[guess] < target) min = guess + 1;
   if (list[guess] > target) max = guess - 1;
 }
}