จะ คูณ textbox กับ php ยังไงหรอครับ พอมีตัวอย่างไหมครับ

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript">
$(document).ready(function(){
    var allowance = 0;
    var bonus = 0;
    $("input.bonus").keyup(function(){
        bonus = $(this).val();
        allowance = $(this).parent().prev().text();
        $(this).parent().next().find("input.linetotal").val( parseFloat(allowance) * parseFloat(bonus) );
    });
});
</script>

<table>
   <tr>
      <td>Lusan</td><td>1000</td>
      <td><input type="text" name="bonus[]" class="bonus" /></td>
      <td><input type="text" name="linetotal[]" class="linetotal" /></td>
   </tr>
   <tr>
      <td>Somdet</td><td>1000</td>
      <td><input type="text" name="bonus[]" class="bonus" /></td>
      <td><input type="text" name="linetotal[]" class="linetotal" /></td>
   </tr>
   <tr>
      <td>Pinyo</td><td>1000</td>
      <td><input type="text" name="bonus[]" class="bonus" /></td>
      <td><input type="text" name="linetotal[]" class="linetotal"  /></td>
   </tr>
</table>