在超链接php中获取单循环表单数据

I am trying to update quantity as i fill the quantity field and click on update button. It works but it shows the form fields of each item in the loop and works for the last entry update only. Something like this.

/EcommerceClient/index.php?page=cart&action=update&id=3&name=%09%0D%0ACool+T-shirt&color=blue&size=XL&quantity=4&id=4&name=HBD+T-Shirt&color=yellow&size=XL&quantity=900

In the above link it should only get the information associated with id=3 only because i tried to update the quantity of id=3.

Here is my code. Any suggestions or help will be highly appreciated.

Code

if(isset($_GET['action']) && $_GET['action']=="update"){

    $id=  intval($_GET['id']);
    $size = $_GET['size'];
    $color = $_GET['color'];
    $qty = $_GET['quantity'];
    $index = $id." ".$color. " ".$size;
if( isset($_SESSION['cart'][$index]) && isset($_SESSION['cart'][$index]['color']) && $_SESSION['cart'][$index]['color'] == $color && isset($_SESSION['cart'][$index]['size']) && $_SESSION['cart'][$index]['size'] == $size){

    $_SESSION['cart'][$index]['quantity']=$qty;

    print_r($_SESSION['cart'][$index]);//It just shows me the last item array.
}
}
?>
<form class="product" method="get" action="index.php">
    <table>
    <input type="hidden" name="page" value="cart">
    <input type="hidden" name="action" value="update">
        <?php
        if(isset($_SESSION['cart'])){
            foreach($_SESSION['cart'] as $id => $value){
         ?>
                <tr>
                        <input type="hidden" name="id" value="<?php echo $value['id'] ?>">
                        <input type="hidden" name="name" value="<?php echo $value['name'] ?>">
                        <input type="hidden" name="color" value="<?php echo $value['color'] ?>">
                        <input type="hidden" name="size" value="<?php echo $value['size'] ?>">


                   <td><?php echo $value['id'] ?></td>
                        <td><?php echo $value['name']?></td>
                        <td><?php echo $value['price']?> </td>
                        <td><?php echo $value['quantity']?><input type="text" name="quantity"  value="<?php echo $value['quantity'] ?>"></td>
                        <td><?php echo  $value['color'];?> </td>
                        <td><?php echo $value['size']; ?></td>
                       <td><?php echo "$" .$value['price']*$value['quantity']. ".00"; ?>
                 </tr>

        <?php
            }
        }

        ?>
        <tr><td><button type="submit">Update</button></td></tr>
    </table>

</form>

You can update the quantity by not posting or getting all the cart product. Either you can use simple JS to update the field value or use SESSION variable array to update data as @Marc B mentioned.