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What is XUL?

XUL is a user interface description language. It is useful to develop rich web applications in the browser space, without dealing with complex javascript and dom manipulations. See http://developer.mozilla.org/en/XUL.

Note : Only Gecko-based browser renders XUL (Firefox is the most famous one).

jResponseXul and friends

The base class for XUL response is jResponseXul. There are also derived class for specific UI elements. List of XUL responses :

  • jResponseXul generates a XUL window (<window>).
  • jResponseXulDialog is for dialogs (<dialog>).
  • jResponseXulOverlay for XUL overlays (<overlay>)
  • jResponseXulPage is for XUL window included in another XUL via <iframe>

As jResponseHtml, jResponseXul generates its main tag but also links to stylesheets, javascripts scripts and overlays (static or dynamic).

Generating XUL

Here is the different XUL response aliases :

  $window = $this->getResponse("xul");
  $dialog = $this->getResponse("xuldialog");
  $overlay = $this->getResponse("xuloverlay");
  $page = $this->getResponse("xulpage");

Below, we'll use $window but all examples work with other responses except contrary indications.

You can add attribute to XUL response main tag (<window>, <overlay>, <dialog> or <page>):

  $window->rootAttributes = array("width"=>"300");

Linking stylsheets, scripts or overlays to XUL response is done through calls to methods addCssLink(), addJsLink() and addOverlay() :


Generating without template

If you don't want to use a template, you'll have to call addContent method to populate your XUL response.

   $rep->addContent('xul content');

Generating with a template

$body member property defines a jTpl object. $bodyTpl should be assigned the template selector to use. And $title is to set the window title.

 $window->title = "my super title";
 $window->bodyTpl = "mymodule~xullist";
 $window->body->assign("list", $list);

As jResponseHtml, you can include content before or after template content. Use addContent() method. It takes a content string as first argument and a boolean (optional) to indicate wether the content should be generated before (true) or (after, defaukt value) template content.

$rep->addContent('XUL after template');
$rep->addContent('XUL before template', true);

You can also use zones for content. See zones documentation.


An overlay is a XUL file. It is useful to modify a XUL page without modifying its source. Firefox extensions use overlays extensively. It can be also useful in a web application and Jelix of course. A module could overload a XUL page of another module using an overlay.


the basics are truely simple, it is based on jelix events system. jResponseXul and its derived class, emits an event before sending content. Modules can catch this event and respond to it with an overlay url. if so, a <?xul-overlay> tag will be added to the response.

the action using jResponseXul has to set $fetchOverlays to true :

  $window->fetchOverlays = true;

if $fetchOverlays is not set, no event will be emitted and thus no extern overlays will be included in the response.

use case

Create a jResponseXulOverlay response. Say it is action "testa~xul:overlay1" and "testb~xul:index" is the action displaying a XUL page where the overlay should apply.

In "testa" module, an event listener should respond to "FetchXulOverlay" event emitted by jResponseXul used in module "testb" action xul:index. In a file, clases/testa.listener.php, you should have:

class testaListener extends jEventListener{

   function onFetchXulOverlay($event){


FetchXulOverlay event as a parameter "tpl", which value is the template selector used by "testb~xul:index" action. Imagine this selector is "testb~mainxul". If this template corresponds to your overlay, you will respond to the event indicating an overlay url.

class testaListener extends jEventListener{

   function onFetchXulOverlay($event){
      if($event->getParam('tpl') == 'testb~mainxul'){

Do not forget to declare this listener in events.xml file of "testa" module:

<events xmlns="http://jelix.org/ns/events/1.0">
   <listener name="testa">
       <event name="FetchXulOverlay" />

There you are, overlay1 of module "testa" will be loaded with page xul:index of module "testb".