floopy function

var s = '';

floop = function(s) {
  var ss = '',
  i = s.length,
  j = 0;

  while () {

    ss = s[i] + ss;
    if (++j >= s.length) {
      break;
    }
  }
  return ss.toString();
}
var r = floop(s);
console.log(r);
alert(r);