In Version 4.29 I've simplified the method for displaying popup messages on a Form.
For an example, see example number 3. You will see this has resulted in a simplification of all the examples that do logins.
How it works
set a local variable (loc:alert) when you set loc:invalid.
The contents of loc:alert will be displayed as a popup message when the form is re-loaded.
It will also be displayed as a message on the form, just below the sub-header of the form. The CSS Class of this message is set on the CSS Classes tab (Alert:).
If you wish to suppress the popup, and display only the message, the tick off the option on the Advanced tab ("Popup Alert Message")
Advanced:
This feature works on the existance of a Value called ALERT. So if you would like to call a form, and include a popup message when the form opens, then you can append the parameter to the URL. For example:
'MySurveyForm?Alert=You must be over 18 to take this survey'
Considerations for those upgrading from 4.28 or earlier
If you have used a technique based on the login examples (In other words a combination of the XHTML tab, and the DisplayLoginMessage, and PopupLoginMessage procedures) then you might want to revise it to use this new (easier) approach.
Cheers
Bruce