code: function (str, start, end, regexp) {
              var currentCharPos = start, whiteRegexp = regexp || /\s/, currentChar;
              while (currentCharPos < end) {
                  currentChar = str.charAt(currentCharPos);
                  if (whiteRegexp.test(currentChar)) {
                      return currentCharPos;
                  }
                  currentCharPos++;
              }
              return -1;
          }
docs: Find next white space in the given string after start position and before end position
  @param {String} str The string into which we search
  @param {Integer} start The position in str at which we should begin the search (included)
  @param {Integer} end The position in str at which we should end the search (excluded)
  @param {RegExp} regexp The regular expression used to recognize a white space. If not provided, /\s/ is used.
  @return {Integer} the position of the whitespace in str (between start and end), or -1 if it was not found