ZK will check if a session attribute called px_preferred_time_zone is defined. If defined, it uses as the default time zone for the session instead of the system default. Thus, you can control the time zone of a session by storing the preferred locale in this attribute, after, say, a user logins as depicted in the previous section.

Tip: To avoid typo, you can use the constant called PREFERRED_TIME_ZONE defined in the org.zkoss.web.Attributes class.