微信小程序 生成唯一字符串

//生成唯一字符串
function create_uuid() {
     
  var s = [];
  var hexDigits = "0123456789abcdef";
  for (var i = 0; i < 36; i++) {
     
    s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
  }
  s[14] = "4"; // bits 12-15 of the time_hi_and_version field to 0010
  s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1); // bits 6-7 of the clock_seq_hi_and_reserved to 01
  s[8] = s[13] = s[18] = s[23] = "-";

  var uuid = s.join("");
  return uuid;
}