Include HTML (Bootstrap Modal Box) with a plugin into my header
You only need the_content filter to add the modal, but bootstrap.js is needed to make it work. add_action(‘wp_enqueue_scripts’, array($this, ‘enqueue_bootstrap’); public function enqueue_bootstrap(){ wp_register_script( ‘bootstrap’, plugins_url( ‘your-plugin/assets/js/bootstrap.min.js’ ) ); wp_enqueue_script( ‘bootstrap’ ); } EDIT: You need to add $content argument to your function. As the codex says Note that the filter function must return the … Read more