XForms ~ XBL ~ Bindings

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Introduction

An XBL file contains one or more bindings, expressed with the xbl:binding element:

<xbl:binding
  id="fr-number"
  element="fr|number, xf|input:xxf-type('xs:decimal')"
  xxbl:mode="lhha binding value focus">

The binding:

• describes the component's markup and behavior
• determines which XML elements, in the source form, it associates with

Binding selectors

The element attribute specifies, via one or more CSS selectors, which XML elements, in the source form, it associates with. The following CSS selectors are supported:

• by element name
• by element name and XML datatype (Form Builder only)
• by attribute only [SINCE Orbeon Forms 4.9]
• by element name and attribute [SINCE Orbeon Forms 4.9]

The simplest way is to bind by element name:

element="fr|number"

This means that elements called fr:number in the form will use this binding.

Form Builder, at design time only (as of Orbeon Forms 4.9), also supports bindings by name and XML datatype:

xf|input:xxf-type('xs:decimal')

This means that an input field bound to an xs:decimal or xf:decimal type will be bound, at design time, by the fr:number binding as well.

NOTE: In the future, we would like such bindings to work at runtime as well, see #1248.

[SINCE Orbeon Forms 4.9]

It is possible to associate bindings by:

• attribute only
• or by name and attribute

The following matches elements such as <fr:charcounter> (by name) but also <foo:bar appearance="cool charcounter stuff">:

element="fr|charcounter, [appearance ~= charcounter]"

The following matches elements having the charcounter appearance and which, at the same time, have the name foo:bar:

element="foo|bar[appearance ~= charcounter]"

The following standard CSS operations on attributes are supported: =, ~=, |=, ^=, $=, *=.