Webform Server cannot remotely set the user's locale. The locale viewed by the user will be determined by the user's browser, not the form. This means that Webform Server browser elements - such as dialogs and the toolbelt - will be in the browser locale while the form will be shown using the form's locale.
If you are using the Viewer with a Webform Server application (for example, using Webform Server to deliver XFDL forms embedded within HTML pages for users that have the Viewer installed on their system), the locale of the Viewer may not be the same as the locale of the form. Webform Server cannot specify the locale of the Viewer. The Viewer's locale is always determined based on the Webform Server preferences.
The default locale is the locale of the operating system.
Parent topic: Differences Between Webform Server and IBM Forms Viewer