Improve JS regexp for email addresses

UI/WebServerResources/generic.js

@@ -118,7 +118,7 @@ function extractEmailAddress(mailTo) {
     var email = "";
 
     var emailre
-        = /([a-zA-Z0-9\._-]*[a-zA-Z0-9_-]+@[a-zA-Z0-9\._-]*[a-zA-Z0-9])/;
+        = /([a-zA-Z0-9\._\-]*[a-zA-Z0-9_\-]+@[a-zA-Z0-9\._\-]*[a-zA-Z0-9])/;
     if (emailre.test(mailTo)) {
         emailre.exec(mailTo);
         email = RegExp.$1;