function IsNum(u)
{
   var i = 0;
   RC = true;
   while (RC && (i < u.length ))
   {
      if (! ((u.charAt(i) >= "0" && u.charAt(i) <= "9") || u.charAt(i) == "."))
      { RC=false; }
      i++;
   }
   return RC;
}

function submitIt(form) {
 if(!IsNum(form.year.value)) {
   alert("Use numeric characters only!")
   form.year.focus()
   form.year.select()
   return false
 }
 return true
}