Popup form for woocommerce

functions.php

function ot_popup_form()
{
    if (is_singular('product')):

        ?>
        <div id="dathang" class="lightbox-by-id lightbox-content mfp-hide lightbox-white" style="padding: 20px;">
            <div class="row">
                <div class="col medium-6">
                    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Accusantium animi autem cumque eum iste
                        itaque, laboriosam maiores minima necessitatibus neque numquam, odio pariatur quaerat, quam
                        quia. Beatae provident sequi voluptas.</p>
                </div>
                <div class="col medium-6">
                    <?php echo do_shortcode('[contact-form-7 id="10" title="Contact form"]'); ?>
                </div>
            </div>

        </div>

        <?php

    endif;
}

add_action('wp_footer', 'ot_popup_form');

function ot_popup_btn()
{
    ?>
    <a href="#dathang" class="button">Yêu cầu tư vấn</a>
    <?php
}

add_action('woocommerce_before_add_to_cart_form', 'ot_popup_btn');