Added window.console IE9 workaround.

src/assets/js/backend.js

@@ -13,6 +13,10 @@
  * Main javascript code for the backend of Easy!Appointments.
  */
 $(document).ready(function() {
+    if (window.console === undefined) {
+        window.console = function() {} // IE compatibility
+    }
+
     $(window).resize(function() {
         Backend.placeFooterToBottom();
     }).trigger('resize');

src/assets/js/frontend_book.js

@@ -41,6 +41,10 @@ var FrontendBook = {
             manageMode = false; // Default Value
         }
 
+        if (window.console === undefined) {
+            window.console = function() {} // IE compatibility
+        }
+
         FrontendBook.manageMode = manageMode;
 
         // Initialize page's components (tooltips, datepickers etc).