//code from http://caibaojian.com/js-random-string.htmlfunction makeid(){  var text = "";  var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";  for( var i=0; i < 5; i++ )    text += possible.charAt(Math.floor(Math.random() * possible.length));  return text;}

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;}

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;}

var randomValue = randomString(5);var randomValue = randomString(5, 'PICKCHARSFROMTHISSET');