show a discreet error when there is an ajax-error on the beamer

openslides/static/javascript/beamer.js

@@ -9,11 +9,10 @@ function presentation_reload() {
                 $('#content').html(data.content);
                 document.title = data.title;
                 $('#currentTime').html(data.time);
-                setTimeout("presentation_reload()",500);
-
+                setTimeout("presentation_reload()", 500);
             },
             error: function () {
-                alert("Ajax Error");
+                $('#currentTime').addClass('ajax_error');
             }
         });
     }

openslides/static/styles/beamer.css

@@ -57,6 +57,10 @@ body{
     background: url(../images/icons/clock.png) no-repeat scroll 0px 4px;
 }
 
+#currentTime.ajax_error {
+    border-bottom: 4px solid red;
+}
+
 /*** CONTENT ***/
 #content {
     position:absolute;