XBL

What is WBL?

XBL stands for eXtensible Bindings Language, which is an XML language that is used for declaring the behavious of XUL widgets.

What Does XBL Do?

Basically, XBL is a langauge that describes a set of bindings that can be attached and bound to elements on the screen. When bound, the binding implements new methods and properties to the associated element. In essence, the widgets on the screen are layed out using XUL and then given functionality using XBL.

Resources/Examples

Test Cases

In this example, we can use XUL to define the layout of user interface and then use XBL to change the widgets functionality.

Here is the XUL Code that lays out the widgets:

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<?xml-stylesheet href="chrome://example/skin/example.css" type="text/css"?>

<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <box class="okcancelbuttons"/>
</window>

This lays out an interface with the buttons for OK and Cancel. To give these buttons functionality, XBL is used:

<?xml version="1.0"?>
<bindings xmlns="http://www.mozilla.org/xbl" xmlns:xul="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <binding id="okcancel">
    <content>
      <xul:button label="OK"/>
      <xul:button label="Cancel"/>
    </content>
  </binding>
</bindings>