php - how to save data dynamically to database

JQUERY CODE

 $(document).ready(function () {
    $("#add").click(function () {
        $(".left .inputs").append("
");
        $(".right .inputs").append("
");
    });
 });

MY PHP CODE

    $con = mysql_connect ("localhost","root","") or die('cannot connect to database error: '.mysql_error());
    if (isset($_POST['name']) && isset($_POST['grade']))
    {

        $desk_report = $_POST['name'];//contains array value
        $desk_action = $_POST['grade'];//contains array value
        foreach($desk_report as $key=>$user) { //Loop through arrays
            if (!empty($desk_report[$key]) && !empty($desk_action[$key])) {

                mysql_select_db("quickbook", $con);
                $sql = "INSERT INTO student_reg(relative_name,relative_grade) VALUES ('$desk_report[$key]','$desk_action[$key]')";
                if ($sql_run = mysql_query($sql)) {
                    echo 'ok.'; 
                } else {
                    echo '*Sorry, we couldn\'t register you at this time. Try again later.';
                }
            }
        }
    }

?>

I want to add inputs data to database.i created a code.but this is not working .can you help me?