Index: openacs-4/packages/acs-subsite/www/register/index.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-subsite/www/register/index.tcl,v
diff -u -r1.14.2.3 -r1.14.2.4
--- openacs-4/packages/acs-subsite/www/register/index.tcl	20 May 2016 20:02:44 -0000	1.14.2.3
+++ openacs-4/packages/acs-subsite/www/register/index.tcl	27 May 2016 16:08:37 -0000	1.14.2.4
@@ -6,6 +6,12 @@
     {username ""}
     {email ""}
     {return_url:localurl ""}
+} -validate {
+    valid_email -require email {
+        if {![regexp {^[\w.@+/=$%!*~-]+$} $email]} {
+            ad_complain "invalid email address"
+        }
+    }
 }
 
 set subsite_id [ad_conn subsite_id]