<form action='?hello' onsubmit='if(!curid) return true;var x=document.forms[0]["id"+(curid+1)]; if(!x)return true;x.focus();return false;'>
<input type="text" onfocus="curid=1" name="id1">
<input type="text" onfocus="curid=2" name="id2">
<input type="text" onfocus="curid=3" name="id3">
<input type="text" onfocus="curid=4" name="id4">
<input type="text" onfocus="curid=5" name="id5">
<input type="submit" onfocus="curid=0" value="Go">
</form>