Information AboutXul |
| CATEGORIES ABOUT XUL | |
| user interface markup languages | |
| xml-based standards | |
| mozilla | |
| rdf data access | |
XUL (pronounced ''zool'' ()), the '''''X'''ML '''U'''ser Interface '''L'''anguage'', is an XML User Interface Markup Language developed by the Mozilla project for use in its cross-platform applications, such as Firefox . The only complete implementation of XUL is the Gecko layout engine. XUL relies on multiple existing web standards and technologies, including CSS , JavaScript , and DOM , which makes it relatively easy to learn for people with a background in web programming and design. XUL and web developer documentation is available from the Mozilla Developer Center {Link without Title} . XUL has no formal specification or interoperable non- Gecko implementations and therefore may be described as an internal or proprietary language. On the other hand, its implementation (Gecko) is open source and Mozilla provides experimental XULRunner builds to let developers build their applications on top of the Mozilla Application Framework and XUL in particular. The main benefit of XUL is that it provides a simple and Portable definition of common Widget s. This reduces the Software Development effort in a way Analogous to the savings offered by 4GL tools. For more information, refer to the Joy of XUL article on developer.mozilla.org. Other User Interface Markup Language s are MXML , Laszlo XML , UIML , and XAML . XUL DOCUMENTS A XUL interface is typically defined to consist of three discrete sets of components:
XUL elements XUL defines a wide range of elements, which roughly belong to the following types: ; Top-level elements: e.g., Window , page, Dialog , Wizard , etc. ; Widgets : e.g., label, Button , Text Box , list box, Combo Box , Radio Button , Check Box , Tree , Menu , Toolbar , group box, Tab Box , color picker, spacer, splitter, etc. ; Box model: e.g., box, grid, stack, deck, etc. ; Events and Scripts: e.g., script, command, key, broadcaster, observer, etc. ; Data source: e.g., template, rule, etc. ; Others: e.g., overlay (analogous to SSI , but client side and more powerful), iframe, browser, editor, etc. It is possible to use elements from other applications of XML within XUL documents, such as XHTML , SVG , and MathML . Some common widgets - Firefox 3 for developers . XUL APPLICATIONS While XUL is mostly used for creating the Mozilla applications and their extensions, it is possible to use it for Web Application s transferred over HTTP . One of the most well-known XUL applications of this type is the Mozilla Amazon Browser , which provides a rich interface for searching books at Amazon.com . However, many of the powerful features of Mozilla, like privileged XPCOM objects, are not available to unprivileged XUL documents (unless the script is Digitally Signed and user granted certain privileges to the application), and such documents also suffer from various limitations of the browser, such as the inability to load remote XUL, DTD, and RDF documents. Because the only full implementation of XUL is Gecko , such applications are inaccessible to users of browsers that are not based on Mozilla. TRIVIA The XUL name is a reference to the film '' URI at the beginning of every XUL document: : http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul When viewed with a XUL-capable application, the document pointed to displays the slogan in large letters in the center of the screen (similar to that to the right). "Keymaster" and "gatekeeper" are also references to the same plotline. This is not the only reference to Ghostbusters within Mozilla - for instance, the JavaScript Debugger component is called Venkman , after One Of The Main Characters in the film. SEE ALSO
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