Processing instructions can be used to modify the way the UI
definition is interpreted. Currently, all processing instructions
must be directly contained in the ui:application
<?wd-debug-mode?>: In debug mode, the
generated HTML code contains a number of comments showing the current
state of the dialog. Although these comments are not rendered by
browsers, you can view them by selecting the "View source code"
function of the browser.
The state is shown as a long XML expression, even including
some inner comments to improve the readability. There are two styles
to encode the XML expression:
This is style is intended for browsers that do not decode text
occuring in comments (e.g. Internet Explorer, Mozilla). Only
"-->" is converted to "==>" to avoid that the outer comment is
closed prematurely. This style is the default.
This is style is intended for browsers that do decode text within
comments (e.g. Netscape 4). The characters <, >, and & are
converted to their escaped forms <, >, and &,
<?wd-prototype-mode?>: In prototype mode,
missing definitions for dialog classes are automatically added to the
universe of dialog classes. These definitions are "empty", i.e. nothing
is done in prepare_page, and nothing happens in handle.
The prototype mode is useful to design dialogs without changing the
<?wd-onstartup-call-handle?>: This mode
forces that the handle method is called even if no event has
been recognized. Normally, the handle method is not called
in such cases.
When the application is started, i.e. the user has typed in
the URL, there is no event, and because of this normally the first action is
to prepare the first page to display. This processing instruction
changes the behaviour, and the first invoked method is handle,
followed by prepare_page.
submit the current form, and the WDialog routines do not detect that
one of the defined events (from ui:button elements etc.) have happened.
Normally, the invocation of handle is omitted unless this
processing instruction forces its execution.