PROBLEM: PHP strip_tags & multi-dimensional array form parameter

Question

I'm having problems stripping the tags from the textual inputs retrieved from my form so as to do something with them in checkout.php. The input is stored in a multi-dimensional array.

Here's my form:

  echo '<form name="choose" action="checkout.php" method="post" onsubmit="return  validate_second_form(this);">';

        echo '<input type="hidden" name="hidden_value" value="'.$no_guests.'" />';

        if($no_guests >= 1){

            echo '<div class="volunteer">';
                echo '<fieldset>';
                    echo '<legend>Volunteer:</legend>';
                        echo '<label>Table:</label>';
                        echo '<select name="volunteer_table">';
                            foreach($tables as $t){
                                    echo '<option>'.$t.'</option>';
                                }
                        echo '</select><br><br>';
                        echo '<label>Seat number:</label>';
                        echo '<select name="volunteer_seat">';
                            foreach($seats as $seat){
                                    echo '<option>'.$seat.'</option>';
                                }
                        echo '</select><br><br>';
                        //echo '<br>';
                echo '</fieldset>';
            echo '</div>';

            for($i=0;$i<$no_guests;$i++){
                $guest = "guest_".$i;
                echo '<div class="'.$guest.'">';
                    echo '<fieldset>';
                        echo '<legend>Guest '.$i.':</legend>';
                            echo '<label>First Name:</label>';
                            echo '<input type="text" name="guest['.$i.']['.$first_name.']" id="fn'.$i.'">';
                            echo '<label>Surname:</label>';
                            echo '<input type="text" name="guest['.$i.']['.$surname.']" id="surname'.$i.'"><br><br>';

                            echo '<label>Date of Birth:</label> <br>';
                            echo '<label>Day:</label>';
                            echo '<select name="guest['.$i.'][dob_day]">';
                                for($j=1;$j<32;$j++){
                                    echo"<option value='$j'>$j</option>";
                                }
                            echo '</select>';

                            echo '<label>Month:</label>';
                            echo '<select name="guest['.$i.'][dob_month]">';
                                for($j=0;$j<sizeof($month);$j++){
                                    $value = ($j + 1);
                                    echo"<option value='$value'>$month[$j]</option>";
                                }
                            echo '</select>';

                            echo '<label>Year:</label>';
                            echo '<select name="guest['.$i.'][dob_year]">';
                                for($j=1900;$j<$year_limit;$j++){
                                    echo"<option value='$j'>$j</option>";
                                }
                            echo '</select> <br><br>';

                            echo '<label>Sex:</label>';
                            echo '<select name="guest['.$i.']['.$sex.']">';
                                echo '<option>Female</option>';
                                echo '<option>Male</option>';
                            echo '</select><br><br>';

                            echo '<label>Table:</label>';
                            echo '<select name="guest['.$i.']['.$table.']">';
                                foreach($tables as $t){
                                    echo '<option>'.$t.'</option>';
                                }

                            echo '</select><br><br>';
                            echo '<label>Seat number:</label>';
                            echo '<select name="guest['.$i.']['.$seat_no.']">';
                                foreach($seats as $seat){
                                    echo '<option>'.$seat.'</option>';
                                }
                            echo '</select><br><br>';
                            //echo '<br>';
                    echo '</fieldset>';
                echo '</div>';
            }
        }
        else{
            echo '<div id="volunteer">';
                echo '<fieldset>';
                    echo '<legend>Volunteer:</legend>';
                        echo '<label>Table:</label>';
                        echo '<select name="volunteer['.$table.']">';
                            foreach($tables as $t){
                                    echo '<option>'.$t.'</option>';
                                }
                        echo '</select><br><br>';
                        echo '<label>Seat number:</label>';
                        echo '<select name="volunteer['.$seat_no.']">';
                            foreach($seats as $seat){
                                    echo '<option>'.$seat.'</option>';
                                }
                        echo '</select><br><br>';
                        //echo '<br>';
                echo '</fieldset>';
            echo '</div>';
        }
        echo '<input type="submit" value="Submit form">';
    echo '</form>';

here's checkout.php:

if(isset($_POST['guest'])){
foreach($_POST['guest'] as $guest){
    $guest['first_name'] = strip_tags($guest['first_name']);
    $guest['surname'] = strip_tags($guest['surname']);
}
//$_SESSION['guest'] = $guests;
}

Answer 1

You need an & to allow editing of the object.

foreach ($_POST['guest'] as &$guest)