### 算法1 ``` function?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; } ``` ### 算法2 ``` function?guid() { ????return?'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g,?function(c) { ????????var?r = Math.random()*16|0, v = c ==?'x'?? r : (r&0x3|0x8); ????????return?v.toString(16); ????}); } ``` ### 算法3 ``` function?guid() { ????function?S4() { ???????return?(((1+Math.random())*0x10000)|0).toString(16).substring(1); ????} ????return?(S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4()); } ``` ### 算法4 ``` function?uuid(len, radix) { ????var?chars =?'0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split(''); ????var?uuid = [], i; ????radix = radix || chars.length; ????if?(len) { ??????// Compact form ??????for?(i = 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix]; ????}?else?{ ??????// rfc4122, version 4 form ??????var?r; ??????// rfc4122 requires these characters ??????uuid[8] = uuid[13] = uuid[18] = uuid[23] =?'-'; ??????uuid[14] =?'4'; ??????// Fill in random data.? At i==19 set the high bits of clock sequence as ??????// per rfc4122, sec. 4.1.5 ??????for?(i = 0; i < 36; i++) { ????????if?(!uuid[i]) { ??????????r = 0 | Math.random()*16; ??????????uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r]; ????????} ??????} ????} ????return?uuid.join(''); } ``` ### 第5種 ``` Math.random().toString(36).substring(3, 8) ```