1.  /***
    2.  * 
    3.  * 获取请求的UUID，指定长度和进制,如 
    4.  * getUUID(8, 2)   //"01001010" 8 character (base=2)
    5.  * getUUID(8, 10) // "47473046" 8 character ID (base=10)
    6.  * getUUID(8, 16) // "098F4D35" 8 character ID (base=16)
    7.  *   
    8.  */
    9. function getUUID(len, radix) {
    10.   var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');
    11.   var uuid = [], i;
    12.   radix = radix || chars.length;
    13.   if (len) {
    14.     for (i = 0; i < len; i++)
    15.       uuid[i] = chars[0 | Math.random() * radix];
    16.   } else {
    17.     var r;
    18.     uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';
    19.     uuid[14] = '4';
    20.     for (i = 0; i < 36; i++) {
    21.       if (!uuid[i]) {
    22.         r = 0 | Math.random() * 16;
    23.         uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];
    24.       }
    25.     }
    26.   }
    27.   return uuid.join('');
    28. }
    30. getUUID(); // 标准uuid: B2D23AAC-F0AF-4B3B-AEC9-2183508950D5
    31. getUUID(8, 16); // 长度8, 进制16uuid: 2B3056FD