创建含数字字母的随机字符串方法

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;

}

转载自:http://www.jb51.net/article/89605.htm