通过单击图像将值加1到值 - PHP

Question

I guys, I need yo help for this. I have this code, wich shows me the products I have in my shopping cart:

for($i=0;$i<count($_SESSION['productos']);$i++)
{
    $id = $_SESSION['productos'][$i];
    $prods = mysql_query('SELECT * from productos where idprod='.$id.'');
    $row = mysql_fetch_array($prods);
        echo "<tr>";
        echo "<td>" . $row['nombre']; echo "</td>";

        if($_GET[action]=="suma")
        {
         $_SESSION['unidades'][$i] =  $_SESSION['unidades'][$i] + 1;
        }
        elseif($_GET[action]=="resta")
        {
        $_SESSION['unidades'][$i] =  $_SESSION['unidades'][$i] - 1;
        }

        echo "<td><input name=".$i." type='text' value=" . $_SESSION['unidades'][$i]; echo " size='5'/></td>";  
        echo "<td><a href='carro_detalle.php?action=suma'><img src='images/flecharriba.png' width='10x' height='10px'/></a></td>";
        echo "<td><a href='carro_detalle.php?action=resta'><img src='images/flechabajo.png' width='10px' height='10px'/></a></td>";
        echo "<td>" . $row['precio']; echo "</td>";
        echo "<td>" . $row['precio'] * $_SESSION['unidades'][$i]; echo "</td>";
            echo "</tr>";
}

I need to sum 1 unity or rest 1 unity to $_SESSION['unidades'][$i] just to the selected product, when I click the two images respectively. The thing is that when I click, it adds me 1 to all the products. Any easy way of doing this without using $_GET vars? I dont have high knowledge about JavasScript. Thanks!!

Answer 1

You probably should remove your condition from the loop and put it outside of it:

if($_GET[action]=="suma")
{
    $_SESSION['unidades'][$i] =  $_SESSION['unidades'][$i] + 1;
}
elseif($_GET[action]=="resta")
{
    $_SESSION['unidades'][$i] =  $_SESSION['unidades'][$i] - 1;
}


for($i=0;$i<count($_SESSION['productos']);$i++)
{
$id = $_SESSION['productos'][$i];
$prods = mysql_query('SELECT * from productos where idprod='.$id.'');
$row = mysql_fetch_array($prods);
    echo "<tr>";
    echo "<td>" . $row['nombre']; echo "</td>";

    echo "<td><input name=".$i." type='text' value=" . $_SESSION['unidades'][$i]; echo " size='5'/></td>";  
    echo "<td><a href='carro_detalle.php?action=suma'><img src='images/flecharriba.png' width='10x' height='10px'/></a></td>";
    echo "<td><a href='carro_detalle.php?action=resta'><img src='images/flechabajo.png' width='10px' height='10px'/></a></td>";
    echo "<td>" . $row['precio']; echo "</td>";
    echo "<td>" . $row['precio'] * $_SESSION['unidades'][$i]; echo "</td>";
        echo "</tr>";
}