Auto Display results from computation while input Demanded Qty

Hi…

I have forms and I only need to input is the Demanded Qty, and from Demanded Qty that I input it will compute the demanded qty for each Item Code.

Now my problem is I don’t know on how can it possible that while i input the quantity it will also autodisplay the demanded qty for each materials.

Noted: the Demanded Qty that will auto display is display only on the Demanded Qty you input per Items.
For Example:

On Item = P28 i input demanded qty, only on the ItemCode will display the output.

and when i input on P30 the computation will display on the ItemCode for P30.

here is my code:


<?php
   error_reporting(0);
   date_default_timezone_set("Asia/Singapore"); //set the time zone
$con = mysql_connect('localhost', 'root','');

if (!$con) {
    echo 'failed';
    die();
}

mysql_select_db("mes", $con);
?>
<html>
<title>Stock Requisition</title>
<head>
<link rel="stylesheet" type="text/css" href="kanban.css">

<script type="text/javascript">
function compute_quantity(){
    var DemandedQty = document.getElementById('DemandedQty').value;
    var Quantity = document.getElementById('Quantity').value;

    var SubQty = (DemandedQty * Quantity);
}
</script>
</head>
<body>
<form name="stock_requisition" action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
 <div>
<table>
<thead>
<th>Items</th>
<th>Sub Items</th>
<th>Item Code</th>
<th>Demanded Qty</th>
<th>UoM</th>
<th>Class</th>
<th>Description</th>
<th>BIN Location</th>
</thead>
<?php

$DemandedQty = $_POST['DemandedQty'];

$sql = "SELECT DISTINCT Items FROM bom_subitems ORDER BY Items";
$res_bom = mysql_query($sql, $con);

while($row = mysql_fetch_assoc($res_bom)){

    $Items = $row['Items'];
    $Items_ = substr($Items, 12, 3);

echo "<tr>
        <td style='border: none;font-weight: bold;'>&nbsp;<input type='name' value='$Items_' name='Items_[]' id='Items' readonly = 'readonly' style = 'border:none;width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;'></td>
        <td style='border:none;'>&nbsp;</td>
        <td style='border:none;'>&nbsp;</td>
        <td style='border: none;'><center><input type='text' name='DemandedQty[]' id='DemandedQty' value='' size='12' onkeypress = compute_quantity()></center></td>
        </tr>";

$sql = "SELECT Items, SubItems, ItemCode, UoM, Class, Description, BINLocation, Quantity FROM bom_subitems WHERE Items = '$Items' ORDER BY Items"or die(mysql_error());

$res_sub = mysql_query($sql, $con);

 while($row_sub = mysql_fetch_assoc($res_sub)){

     $Items1 = $row_sub['Items'];
     $SubItems = $row_sub['SubItems'];
     $ItemCode = $row_sub['ItemCode'];
     $UoM = $row_sub['UoM'];
     $Class = $row_sub['Class'];
     $Description = $row_sub['Description'];
     $BINLocation = $row_sub['BINLocation'];
     $Quantity = $row_sub['Quantity'];

    echo "<input type='hidden' name='Quantity' id='Quantity' value='$Quantity'>";
    echo "<tr>
        <td style='border: none;'>&nbsp;<input type='hidden' value='$Items1' id='Items1' name='Items1[]'></td>
        <td style='border: none;'>&nbsp;<input type='text' name='SubItems[]' value='$SubItems' id='SubItems' readonly='readonly' style='border:none; width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;'></td>
        <td style='border: none;'>&nbsp;<input type='text' name='ItemCode[]' value='$ItemCode' id='ItemCode' readonly='readonly' style='border:none; width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;'></td>
        <td style='border: none;'><center><input type='text' name='SubQty[]' id='SubQty' value='' size='12' style></center></td>
        <td style='border: none;' size='3'>&nbsp;<input type='text' name='UoM[]' value='$UoM' id='UoM' readonly='readonly' style='border:none; width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;' size='3'></td>
        <td style='border: none;'>&nbsp;<input type='text' name='Class[]' value='$Class' id='Class' readonly='readonly' style='border:none; width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;'></td>
        <td style='border: none;'>&nbsp;<input type='text' name='Description[]' value='$Description' id='Description' readonly='readonly' style='border:none; width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;' size= '30'></td>
        <td style='border: none;'>&nbsp;<input type='text' name='BINLocation[]' value='$BINLocation' id='BINLocation' readonly='readonly' style='border:none; width:auto;font-family: Arial, Helvetica, sans-serif;font-size: 1em;'></td>
        </tr>";

}
}
?>
</table>
</div>

</form>
</body>
</html>


Thank you so much