The first method
/**@desc: Generate random string *@remark:toString method can receive a cardinality as a parameter, and this cardinality is topped from 2 to 36. If not specified, the default radix is decimal*/function generateRandomAlphaNum(len) { var rdmString = ""; for (; rdmString.length < len; rdmString += Math.random().toString(36).substr(2)); return rdmString.substr(0, len);}The second method
//JS generates GUID functions, similar to NewID() in .net; function S4() { return (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1);}function NewGuid() { return (S4() + S4() + "-" + S4() + "-" + S4() + "-" + S4() + "-" + S4() + "-" + S4() + S4() + "-" + S4() + S4());}The third method
//JS generates GUID functions, similar to NewID() in .net; function newGuid() { var guid = ""; for (var i = 1; i <= 32; i++) { var n = Math.floor(Math.random() * 16.0).toString(16); guid += n; if ((i == 8) || (i == 12) || (i == 16) || (i == 20)) guid += "-"; } return guid;}The fourth method
/**@desc: Generate random string *@demo:console.log(ranStr());*/;(function(){ //Number 0-9, uppercase letters, lowercase letters, ASCII or UNICODE encoding (decimal), a total of 62 var charCodeIndex = [[48,57],[65,90],[97,122]]; var charCodeArr = []; function getBetweenRound(min,max){ return Math.floor(min+Math.random()*(max-min)); }; function getCharCode(){ for(var i=0,len=3;i<len;i++){ var thisArr = charCodeIndex[i]; for(var j=thisArr[0],thisLen=thisArr[1];j<=thisLen;j++){ charCodeArr.push(j); } } } function ranStr(slen){ slen = slen || 20; charCodeArr.length<62 && getCharCode(); var res = []; for(var i=0;i<slen;i++){ var index = getBetweenRound(0,61); res.push(String.fromCharCode(charCodeArr[index])); } return res.join(''); }; this.ranStr = ranStr;})();