function uuid2() {
                    var s = [];
                    var hexDigits = "0123456789abcdef";
                    for (var i = 0; i < 32; 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;
                }