code: function extractString_(full, start, end) {
    var i = (start === '') ? 0 : full.indexOf(start);
    var e = end === '' ? full.length : full.indexOf(end, i + start.length);
    return full.substring(i + start.length, e);
  }
docs: Extract the substring from full string, between start string and end string
  @param {String} full
  @param {String} start
  @param {String} end