JS创建随机数

         function makeRandChar(chars,marklen)

        {//创建随机数

            var tmpstr = '';

            var chrlen = chars.length;

            var iRandom ;

            do{

                iRandom = Math.round(Math.random() * chrlen);

                tmpstr += chars.charAt(iRandom);

                if( tmpstr.length == marklen ) break;    

            }while (tmpstr.length < marklen)

            return tmpstr;

        }

创建随机数.
var randLength = 5;
var randStr = "1234567890";
var randNum = randStr (chars,randLength );

alert(randNum );