Fixed slidr error (cannot find element with id 'slidr-div')

App/Views/Data/pengumuman.html

@@ -113,11 +113,13 @@
 </main>
 
 <script>
-    slidr.create('slidr-div', {
-        controls: false,
-        timing: {'linear': '0.5s ease-in'},
-        theme: '#666',
-        touch: true
-    }).add("h", [{% for post in posts %}"{{ post.id }}", {% endfor %} {% if posts|length > 1 %}"{{ posts.0.id }}"{% endif %}]).start().auto();
+    if (document.getElementById('slidr-div')) {
+        slidr.create('slidr-div', {
+            controls: false,
+            timing: {'linear': '0.5s ease-in'},
+            theme: '#666',
+            touch: true
+        }).add("h", [{% for post in posts %}"{{ post.id }}", {% endfor %} {% if posts|length > 1 %}"{{ posts.0.id }}"{% endif %}]).start().auto();
+    }
 </script>
 {% endblock %}