javaScript生成GUID的方法

function guid() {    function S4() {       return (((1+Math.random())*0x10000)|0).toString(16).substring(1);    }    return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());}

二、生成GUID的方法二

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);    });}

三、生成GUID的方法三

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;}

四、生成GUID的方法四

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