The XML Binding Language (XBL) describes the ability to associate elements in a document with script, event handlers, CSS, and more complex content models, which can be stored in another document.
This can be used to re-order and wrap content so that, for instance, simple HTML or XHTML markup can have complex CSS styles applied without requiring that the markup be polluted with multiple semantically neutral div elements.
It can also be used to implement new DOM interfaces, and, in conjunction with other specifications, enables arbitrary tag sets to be implemented as widgets. For example, XBL could be used to implement the form controls in XForms or HTML.
XBL specification is developed by W3C.
