XForms

The main goal of XForms is to make web forms design easier, allowing the developer to write less client-side scripting (or none at all), and less server-side code thanks to a feature-rich declarative approach.

Benefits of XForms include:

• Clear separation between data captured and presentation (separation of concerns)
• Flexible, structured XML-based data model: define your data model as an XML document, then create forms accessing the data
• Built-in facilities for validation and data integrity based on XML Schema and/or assertions
• Declarative approach requiring less / no scripting at all, in particular thanks to declarative events and actions
• Ease of internationalization
• Support for a variety of devices
• W3C standard
• Not tied to a particular platform or language such as Java or .NET

The key is to understand that you can't directly add data to an element the way you would with a plain HTML page. Instead, you need to put the information into the instance and then manipulate the XPath statement that specifies the contents of an XForms control.

The W3C on XForms.