XForms Basics, Part 3

Endgame

In the previous article, I showed you how to manage user input in the XForms model. I discussed the process of submitting an XForm and – more importantly - validating user input prior to submission using built-in XML Schema support.

In this concluding segment, I'll introduce you to some of XForms' more arcane features. First, the concept of binding, which allows developers to implement a number of useful features quickly: calculating values instantly, enforcing basic validation rules, taking decisions on the fly, or rendering a particular node non-writable.

Next, I'll briefly show you how you can use XPath functions within an XForms model definition, and illustrate how functions like sum() and avg() allow you to perform complex calculations in a simple and smooth manner. I'll also take a quick look at the XForms event processing model, explaining the important phases and showing you a basic example of how triggers and actions work.

Let's get started, shall we?