1 files changed, 13 insertions, 10 deletions
diff --git a/www/js/utils.js b/www/js/utils.js
index 8a7ee9c..b8bfee7 100644
--- a/www/js/utils.js
+++ b/www/js/utils.js
@@ -53,17 +53,20 @@ weekday[6] = 'Samstag';
 var weekday_short = new Array('So', 'Mo', 'Di', 'Mi', 'Do', 'Fr', 'Sa');
 
 function format_datetime(d) {
-  if(Object.prototype.toString.call(d) === '[object Date]') {
-    var datetimestr = weekday_short[d.getDay()];
-    datetimestr += ' ' + Number(d.getDate()).pad(2);
-    datetimestr += '.' + Number(d.getMonth() + 1).pad(2);
-    datetimestr += '.' + d.getFullYear();
-    datetimestr += ' ' + Number(d.getHours()).pad(2);
-    datetimestr += ':' + Number(d.getMinutes()).pad(2);
-    datetimestr += ':' + Number(d.getSeconds()).pad(2);
-    return datetimestr;
+  if(Object.prototype.toString.call(d) !== '[object Date]') {
+    return d;
   }
-  return d;
+  if (d.toString() === 'Invalid Date') {
+    return d;
+  }
+  var datetimestr = weekday_short[d.getDay()];
+  datetimestr += ' ' + Number(d.getDate()).pad(2);
+  datetimestr += '.' + Number(d.getMonth() + 1).pad(2);
+  datetimestr += '.' + d.getFullYear();
+  datetimestr += ' ' + Number(d.getHours()).pad(2);
+  datetimestr += ':' + Number(d.getMinutes()).pad(2);
+  datetimestr += ':' + Number(d.getSeconds()).pad(2);
+  return datetimestr;
 }
 
 function msToTimeString(time) {