<script>
var tmp=new Array();
tmp[ 0 ]=new Array();
tmp[ 1 ]=new Array();

select_b=new Array();
select_b[ 0 ]='0_0';
select_b[ 1 ]='0_1';

select_b[ 2 ]='1_0';
select_b[ 3 ]='1_1';

tmp[ 0 ][ 0 ]= 0 ;
tmp[ 0 ][ 1 ]= 1 ;

tmp[ 1 ][ 0 ]= 2 ;
tmp[ 1 ][ 1 ]= 3 ;

function reselect(value)
{
   var my_select;
   var i;

   my_select=document.getElementById('b');
   my_select.options.length= 0 ;

   for(i in tmp[value])
   {
      my_select.options[i]=new Option(select_b[tmp[value][i]], i);
   }
}
</script>

<select name='a' id='a' onChange='reselect(this.value)'>
 <option value='0'> 0 </option>
 <option value='1'> 1 </option>
</select>

<select name='a' id='a' onChange='reselect(this.value)'>
 <option value='0'> 0 </option>
 <option value='1'> 1 </option>
</select>

<select name='b' id='b'>
</select>
<script>reselect( 0 )</script>

<select name='a' id='a' onChange='reselect(this.value)'>
 <option value='0'> 0 </option>
 <option value='1'> 1 </option>
</select>

$tmp_code="";
for($i= 0 ;$i< 100 ;$i++)
{
   $select_a_code.="
   <option value=$i>$i</option>";

   $tmp_code.="tmp[".$i. "]=new Array();";
   for($j= 0 ;$j< 100 ;$j++)
   {
      $k=$i* 100 +$j;

      $select_b_code.="
      select_b[$k]='".$i. "_".$j. "';";
      $tmp_code.="
      tmp[".$i. "][".$j. "]=".$k. ";";
   }
}
$code="

<script>
var tmp=new Array();
select_b=new Array();
$select_b_code

$tmp_code

function reselect(value)
{
   var my_select;
   var i;

   my_select=document.getElementById('b');
   my_select.options.length=0;

   for(i in tmp[value])
   {
      my_select.options[i]=new Option(select_b[tmp[value][i]], i);
   }
}
</script>

<select name='a' id='a' onChange='reselect(this.value)'>
$select_a_code
</select>

<select name='b' id='b'>
</select>
<script>reselect(0)</script>
";

echo $code;