Question

I’m trying to add the CSS class “selected” to the first accordionButton div created. Why doesn’t this work?

// Create nav from database
                $chapter_array = get_chapter_names();

                for ($i=0; $i < sizeof($chapter_array); $i++) { 
                    if($i == 0) {
                        $selected = 'selected';
                    }
                    echo '<div class="accordionButton '.$selected.'">'.$chapter_array[$i].'</div>';

                    $page_id_array = get_page_ids($i);

                    echo '<div class="accordionContent">';
                    for ($j=0; $j < sizeof($page_id_array); $j++) { 
                        $page_name = get_page_name($page_id_array[$j]);
                        echo '<a href="?page_id='.$page_id_array[$j].'">'.$page_name.'</a><br />';
                    }
                    echo '</div>';
                }

Answer 1

You never set $selected back after the first div so this adds that class to every div, because $selected always contains the string 'selected'.

You can set it to the empty string before your if statement:

$selected = '';
if($i == 0) {
    $selected = 'selected';
}

If you like this better you can also write that as a nice ternary expression:

$selected = $i == 0 ? 'selected' : '';