Javascript生成全局唯一标识符（GUID,UUID）的方法

方法一

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1function guid() {

2  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {

3    var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);

4    return v.toString(16);

5  });

6}

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方法二

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1function guid() {

2  function S4() {

3    return (((1+Math.random())*0x10000)|0).toString(16).substring(1);

4  }

5  return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());

6}

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 方法三

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1function uuid(len, radix) {

2  var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'.split('');

3  var uuid = [], i;

4  radix = radix || chars.length;

5 

6  if (len) {

7   // Compact form

8   for (i = 0; i < len; i++) uuid[i] = chars[0 | Math.random()*radix];

9  } else {

10   // rfc4122, version 4 form

11   var r;

12 

13   // rfc4122 requires these characters

14   uuid[8] = uuid[13] = uuid[18] = uuid[23] = '-';

15   uuid[14] = '4';

16 

17   // Fill in random data. At i==19 set the high bits of clock sequence as

18   // per rfc4122, sec. 4.1.5

19   for (i = 0; i < 36; i++) {

20    if (!uuid[i]) {

21     r = 0 | Math.random()*16;

22     uuid[i] = chars[(i == 19) ? (r & 0x3) | 0x8 : r];

23    }

24   }

25  }

26 

27  return uuid.join('');

28}

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 这个可以指定长度和基数。比如

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1// 8 character ID (base=2)

2uuid(8, 2) // "01001010"

3// 8 character ID (base=10)

4uuid(8, 10) // "47473046"

5// 8 character ID (base=16)

6uuid(8, 16) // "098F4D35"

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 方法四

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1function uuid() {

2  var s = [];

3  var hexDigits = "0123456789abcdef";

4  for (var i = 0; i < 36; i++) {

5    s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);

6  }

7  s[14] = "4"; // bits 12-15 of the time_hi_and_version field to 0010

8  s[19] = hexDigits.substr((s[19] & 0x3) | 0x8, 1); // bits 6-7 of the clock_seq_hi_and_reserved to 01

9  s[8] = s[13] = s[18] = s[23] = "-";

10 

11  var uuid = s.join("");

12  return uuid;

13}

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方法好用不好用，试了才知道嘛  但密码相对来说肯定长度越长更有意义 阔以避免重复性 也是一大好处