Hiding and Revealing Controls

In our del.icio.us form we could make life easier for our users if we didn't show the Title control until the URL field was completed, and similarly we didn't show the Description control until both the URL and Title were filled in. We could also use the same rules to hide the submit button until there was enough data present to make submission possible.

This is possible in XForms by defining rules that say when a control should be relevant or not; it might be that certain fields are only relevant if someone is self-employed or the property they want to buy is a flat. By defining such rules, the controls on the form are revealed in stages as the user fills data in, making errors less likely, and improving the user experience. Let's see how this is done.