First type:
//code from http://caibaojian.com/js-random-string.html function makeid() { var text = ""; var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"; for( var i=0; i < 5; i++ ) text += possible.charAt(Math.floor(Math.random() * possible.length)); return text; }
Second type: No need to enter character set
function randomstring(L){ var s= ''; var randomchar=function(){ var n= Math.floor(Math.random()*62); if(n<10) return n; //1-10 if(n<36) return String.fromCharCode(n+55); //A-Z return String.fromCharCode(n+61); //a-z } while(s.length< L) s+= randomchar(); return s; } alert(randomstring(5))
Third type: Support custom character length and characteristic character set
function randomString(len, charSet) { charSet = charSet || 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; var randomString = ''; for (var i = 0; i < len; i++) { var randomPoz = Math.floor(Math.random() * charSet.length); randomString += charSet.substring(randomPoz,randomPoz+1); } return randomString; }
Call with default charset [a-zA-Z0-9] or send in your own:
var randomValue = randomString(5); var randomValue = randomString(5, 'PICKCHARSFROMTHISSET');
Demo screenshot
The above is a summary of the three methods of creating random strings containing numbers and letters in JavaScript. You can refer to them if you need them.
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