diff --git a/app/assets/javascripts/calendar_widget.js b/app/assets/javascripts/calendar_widget.js
index 99c2c0c..9419fb2 100644
--- a/app/assets/javascripts/calendar_widget.js
+++ b/app/assets/javascripts/calendar_widget.js
@@ -343,7 +343,7 @@
               }
               events[dt].push(eve)
               td.addClass("w-calendar-event");
-              if(events[dt].length==1){
+              if(events[dt] && events[dt].length==1){
                 td.click(function(){
                   toggle_event(this,'show')
                 })
@@ -360,7 +360,7 @@
               events[dt]=[]
             }
             events[dt].push(eve)
-            if(events[dt].length==1){
+            if(events[dt] && events[dt].length==1){
               td.click(function(){
                 toggle_event(this,'show')
               })
diff --git a/app/assets/javascripts/calendar_widget2.js b/app/assets/javascripts/calendar_widget2.js
index b7ae060..4de987b 100644
--- a/app/assets/javascripts/calendar_widget2.js
+++ b/app/assets/javascripts/calendar_widget2.js
@@ -193,7 +193,7 @@
         if (active_flag){
           event_temp.addClass('active')
         }
-        if (events[date].length>1){
+        if (events[date] && events[date].length>1){
           var switch_button_wraper = $("<div class=\"switch_button_wraper\"> <button class=\"switch_button\" for=\"prev\" type=\"button\">&lt;</button>"
                                       +"<button class=\"switch_button\" for=\"next\" type=\"button\">&gt;</button>"
                                       +"</div>")
@@ -482,7 +482,7 @@
               }
               events[dt].push(eve)
               td.addClass("w-calendar-event");
-              if(events[dt].length==1){
+              if(events[dt] && events[dt].length==1){
                 td.click(function(){
                   toggle_event(this,'show')
                 })
@@ -499,7 +499,7 @@
               events[dt]=[]
             }
             events[dt].push(eve)
-            if(events[dt].length==1){
+            if(events[dt] && events[dt].length==1){
               td.click(function(){
                 toggle_event(this,'show')
               })