diff --git a/functions.php b/functions.php
index 444bb1d..68dae55 100644
--- a/functions.php
+++ b/functions.php
@@ -1,30 +1,35 @@
 <?php
 
 // enable automatic update
-add_filter( 'auto_update_plugin', '__return_true' );
-add_filter( 'auto_update_theme', '__return_true' );
+add_filter('auto_update_core', '__return_true');
+add_filter('auto_update_theme', '__return_true');
+add_filter('auto_update_plugin', '__return_true');
+add_filter('auto_update_translation', '__return_true');
 
-
-add_action('wp_enqueue_scripts', 'theme_enqueue_styles');
-function theme_enqueue_styles() {
-    wp_enqueue_style('parent-style', get_template_directory_uri().'/style.css' );
+// load and overrride style of parent theme
+add_action('wp_enqueue_scripts', 'niu_theme_enqueue_styles');
+function niu_theme_enqueue_styles()
+{
+    wp_enqueue_style('parent-style', get_template_directory_uri().'/style.css');
     wp_enqueue_style('child-style', get_stylesheet_directory_uri().'/style.css', ['parent-style']);
 }
 
 // enable archive page.
-add_filter( 'register_post_type_args', 'post_has_archive', 10, 2 );
-function post_has_archive($args, $post_type) {
+add_filter('register_post_type_args', 'niu_post_has_archive', 10, 2);
+function niu_post_has_archive($args, $post_type)
+{
     if ('post' == $post_type) {
         $args['rewrite'] = true;
-	$args['has_archive'] = 'news';
+        $args['has_archive'] = 'news';
     }
 
     return $args;
 }
 
 // add google analytics
-add_action('wp_head', 'hook_google_analytics');
-function hook_google_analytics() {
+add_action('wp_head', 'niu_add_google_analytics');
+function niu_add_google_analytics()
+{
     echo <<<EOF
 
 <!-- Google Tag Manager -->
@@ -37,3 +42,14 @@ j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
 
 EOF;
 }
+
+// disable oembed if url is not my site url
+add_filter('oembed_request_post_id', 'niu_check_oembed_url', 10, 2);
+function niu_check_oembed_url($post_id, $url)
+{
+    if (!preg_match('/^'.preg_quote(get_site_url(), '/').'/', $url)) {
+        return 0;
+    }
+
+    return $post_id;
+}