code: function (str1, str2) {
                var sanitized_str1 = sanitize(str1);
                var sanitized_str2 = sanitize(str2);
                var pairs1 = wordLetterPairs(sanitized_str1);
                var pairs2 = wordLetterPairs(sanitized_str2);
                var intersection = 0, union = pairs1.length + pairs2.length;
                if (union === 0) {
                    if (sanitized_str1 === sanitized_str2) {
                        return 1;
                    } else {
                        return 0;
                    }
                } else {
                  var i, j, pair1, pair2;
                  for (i = 0; i < pairs1.length; i++) {
                    pair1 = pairs1[i];
                    for (j = 0; j < pairs2.length; j++) {
                      pair2 = pairs2[j];
                      if (pair1 == pair2) {
                        intersection ++;
                        delete pairs2[j];
                        break;
                      }
                    }
                  }
                  return 2 * intersection / union;
                }
              }
docs: Compare two strings, and spit out a number from 0-1