a little problem of changing input product number

i have a page of cart that cannot change total amount when i input the quantity

<?php session_start(); header('Content-type: text/html; charset=utf-8'); include_once('../../xajax_core/xajax.inc.php'); // ?? xajax $xajax = new xajax(); // ?? xajax ??

// ??????? $chaObj=$xajax->registerFunction('change_quantity'); $chaObj->useSingleQuote(); $chaObj->addParameter(XAJAX_FORM_VALUES,'form1'); $xajax->processRequest(); // ????

//---------------------- ????? --------------------- // ????????????? function change_quantity($form) {

$objResponse = new xajaxResponse();  // ??????
// ???? Checkbox ??? p_id, ????, ??????
// ?????????? 'p_id' ??, ??????????
// ????????

if(isset($form['p_id'])) {
  // ?????????????
  foreach($form['p_id'] as $p_id) {
    // ???????????????
    if($form['qua'][$p_id]=='0') {
      // ???????? 0, ????????????
      unset($_SESSION['cart'][$p_id]);

      if(count($_SESSION['cart'])==0) {  // ????????
        $objResponse->                   // ?????
          script('alert("?????????");window.close();');
          unset($_SESSION['cart']);
      }
      else  { // ???????????
        // ?????????????
        $objResponse->remove($p_id);

        // ???????????
        $objResponse->assign('total','innerHTML',getTotal());
      }
    }
    else if ($form['qua'][$p_id]>0) {
      // ????? 0 ??, ?????????????
      $_SESSION['cart'][$p_id]['quantity'] = $form['qua'][$p_id];

      // ??????, ?????????????????
      $objResponse->assign('sub[' . $p_id . ']', 'innerHTML',
                           $_SESSION['cart'][$p_id]['quantity'] *
                           $_SESSION['cart'][$p_id]['price']);
      $objResponse->assign('total','innerHTML',getTotal());
    }
    else {
      // ??????, ?????????
      $objResponse->assign('qua[' . $pid . ']', 'innerHTML',
                           $_SESSION[$pid]['quantity']);
    }
  }
}
return $objResponse;          // ??????

} // ???? change_quantity() ??

// ???????? function getTotal() { $total = 0; foreach($_SESSION['cart'] as $p_id => $item) $total += ($item['quantity'] * $item['price']);

return $total;

}

//---------------------- ??? HTML --------------------- // ?????????, ????????????????? if( !isset($_SESSION['cart']) ) { // ??????? echo "<script>alert(\"?????????\");" . "window.close();</script>"; exit(); } ?> <title>?????</title>

<!-- -------------------- ??? JavaScript ------------------ --> <script type="text/javascript"> // ?????????????? checkbox ??? function select_all(formName, elementName, selectAllName) { elem = document.forms[formName].elements[elementName]; if(!elem) // ?????? return; else if(elem.length!= null) // ????????? (elem ???) for(var i = 0; i < elem.length; i++) elem[i].checked = document.forms[formName].elements[selectAllName].checked; else elem.checked = document.forms[formName].elements[selectAllName].checked; }

// ?????????????0, ???????? function settozero(formName, elementName) {

elem = document.forms[formName].elements[elementName]; if(!elem) // ?????? return; else if(elem.length!= null) { // ????????? (elem ???) for(var i = 0; i < elem.length; i++) if(elem[i].checked) { var qua = document.getElementById("qua[" + elem[i].value + "]"); var subtotal = document.getElementById("sub[" + elem[i].value + "]");

    qua.value = 0;  // ????? 0
    subtotal.value = 0;


  }

} else { var qua = document.getElementById("qua[" + elem.value + "]"); var subtotal = document.getElementById("sub[" + elem.value + "]");

qua.value = 0;  // ????? 0
subtotal.value = 0;

} var total_value = document.getElementById("total"); total_value.value = 0; <?php $chaObj->printScript(); // ???????????? ?> } </script> <?php $xajax->printJavaScript('/'); ?>

<!-- ------------------- ???????? ------------------- --> <link rel="StyleSheet" type="text/css" href="../module.css" /> <form name="form1" id="form1" method="post" action="checkout.php"> <table width="800" border="0" align="center" cellspacing="0" cellpadding="2" style="text-align:center;border:1px solid silver"> <tr><th colspan="7">???????</th></tr> <tr style="background-color:silver;color:white"> <td height="23" width="80">?? <!----- ???????????? checkbox -----> <input type="checkbox" name="all" onClick="select_all('form1','p_id[]',this.name);"> </td> <td height="23" width="460">????</td> <td height="23" width="60">??</td> <td width="10" height="23"></td> <td height="23" width="60">??</td> <td width="10" height="23"></td> <td width="70" height="23">??</td> </tr>

<!-- -------------------- ??????? -------------------- --> <?php // ????????? $total = 0; foreach($_SESSION['cart'] as $p_id => $item) { // ???? id ???? $p_id, ??????? echo "<tr id='$p_id'>\n"; echo "<td width='80' height='21'>" . "<input type='checkbox' name='p_id[]' value='" . $p_id . "'></td>\n"; echo "<td>" . $item['name'] . "</td>\n"; echo "<td width='60' >" . $item['price'] . "</td>\n"; echo "<td width='10' style='border-width:0'>×</td>\n"; echo "<td width='60'>" . "<input type='text' name='qua[$p_id]' id='qua[$p_id]' value='" . $item['quantity'] . "' size='3'></td>"; echo "<td width='10' style='border-width:0'>=</td>\n"; echo "<td width='70' align='right'>" ."<input type='text' size='6' id='sub[$p_id]' value='".($item['quantity'] * $item['price'])."' disabled>"."</td></tr>\n"; } ?> <tr> <td align="right" colspan="6">???</td> <td align="right" style="border-top:1px solid silver;width:70"> <input type="text" name="total" value="<?php echo getTotal(); // ?????? ?>" id="total"> </td> </tr> </table>

<!-- -------------------- ?????? -------------------- --> <table width="800" border="0" align="center"> <tr> <td height="23" align="center"> <input type="button" name="DEL" value="????" onClick="settozero('form1','p_id[]')"> </td> <td height="23" align="center"> <input type="button" name="UPD" value="????" onClick="<?php $chaObj->printscript(); ?>"> </td> <td height="23" align="right"> <input type="button" name="CONT" value="????" onClick="window.close();"> </td> <td height="23" align="right"> <input type="button" name="CONT" value="????" onClick="location.href='checkout.php';"> </td> </tr> </table> </form>