Кто поможет написать несложный JavaScript ?

<div id="mD">
<p><input id="f0" alw="1,2,5" rlt="f3">
<p><input id="f1" alw="7">
<p><input id="f2" alw="4">
<p><input id="f3" alw="1,2,5" rlt="f0">
</div>
<p>Îøèáîê: <span id="err">0</span>
<script>
for (var d = document,
         t = d.getElementById ('mD').getElementsByTagName ('input'),
         j = 0, J = t.length; j < J; j++)
   {
   t [j].maxLength = 1; t [j].style.textAlign = 'center';
   if (d.attachEvent) t [j].attachEvent ('onkeyup', mF);
   else if (d.addEventListener) t [j].addEventListener ('keyup', mF, false);
   }
 
function mF ()
   {
   var q = this, p = q.value.length,
       n = q.getAttribute ('alw').split (',');
   for (var k = l = 0, K = n.length; k < K; k++)
      if (q.value == n [k]) {l = 1; break}
   q.style.borderColor = !p ? '' : (l ? '' : 'red');
   if (!l && p) d.getElementById ('err').innerHTML++;
   if (q.getAttribute ('rlt'))
      for (var m = 0, r = q.getAttribute ('rlt').split (','), M = r.length; m < M; m++)
         with (d.getElementById (r [m]))
            value = q.value, style.borderColor = !p ? '' : (l ? '' : 'red');
   }
</script>