<?php
$url = admin_url('admin-ajax.php?action=stm_lms_enable_addon&addon=certificate_builder');
$class = 'disabled';
if(class_exists('STM_LMS_Certificate_Builder')){
    $url = admin_url('admin.php?page=certificate_builder');
    $class = 'enabled';
}
?>
<div class="certificate_banner">
    <a href="<?php echo esc_url($url); ?>" class="<?php echo esc_attr($class); ?>" data-url="<?php echo esc_url(admin_url('admin.php?page=certificate_builder')); ?>">
        <img src="<?php echo STM_LMS_URL; ?>assets/img/cert_builder.jpg" style="display: inline-block; vertical-align: top; margin-bottom: 10px;" />
    </a>
</div>