Message Box Management

When the WTE is running as a service (rather than running in a window), the WTE captures most message boxes and clicks the default button. This is because a WTE application has no user interface (UI) while the WTE is running as a service. Capturing message boxes and clicking the default button helps prevent unexpected message boxes from blocking a WTE application. These unexpected message boxes include those that originate in the operating system or in some other component, such as an ODBC component.

As a WTE application author, you must carefully design and preview your application's pages to prevent any undesired effects that may occur when the WTE clicks the default button in a message box.

The WTE service captures only those pop-up windows and message boxes that are displayed by the Win32® MessageBox and MessageBoxIndirect functions. These functions are typically called under the following circumstances:

• Calling the Microsoft Visual Basic® or Visual Basic Scripting Edition (VBScript) MsgBox function.
• Calling the assert, MessageBox or MessageBoxIndirect function from a C/C++ implementation of an ActiveX object.

Note that the WTE service cannot capture the message box displayed by the window.close method. For this reason, a WTE application should not call window.close while the application is running under the WTE service.

The WTE displays message boxes and pop-up windows stemming from an application's HTML code only when the WTE is running the application in a window. Each application window shows the message boxes and pop-up windows created by the currently loaded HTML page. The application remains blocked until the user dismisses the message box by clicking one of its buttons. Running your WTE application in a window is a convenient way to preview the application. For more information, see Running the Web Telephony Service in Window Mode.