Index: openacs-4/packages/acs-subsite/www/resources/core.js
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-subsite/www/resources/core.js,v
diff -u -r1.17.2.17 -r1.17.2.18
--- openacs-4/packages/acs-subsite/www/resources/core.js	23 Jan 2024 07:39:09 -0000	1.17.2.17
+++ openacs-4/packages/acs-subsite/www/resources/core.js	23 Jan 2024 12:07:22 -0000	1.17.2.18
@@ -1478,9 +1478,10 @@
 
 /** Checks dates equality (ignores time) */
 Date.prototype.equalsTo = function(date) {
-        return ((this.getFullYear() == date.getFullYear()) &&
-                (this.getMonth() == date.getMonth()) &&
-                (this.getDate() == date.getDate()));
+    return date !== null &&
+        this.getFullYear() == date.getFullYear() &&
+        this.getMonth() == date.getMonth() &&
+        this.getDate() == date.getDate();
 };
 
 /** Prints the date in a string according to the given format. */