Please note, this is a STATIC archive of website developer.mozilla.org from 03 Nov 2016, cach3.com does not collect or store any user information, there is no "phishing" involved.

About MDN

The Mozilla Developer Network (MDN) is an evolving learning platform for Web technologies and the software that powers the Web, including:

Our mission

MDN's mission is simple: to provide complete, accurate, and helpful documentation for everything about the open Web, whether it's supported by Mozilla-built software or not. If it's an open technology exposed to the Web, we want to document it.

In addition, we provide documentation about how to build and contribute to Mozilla projects and about Firefox OS and Web app development.

If you're not sure whether a particular topic should be covered on MDN, read: Does this belong on MDN?

How you can help

You don't need to be able to code—or to write—in order to be able to help MDN! We have lots of ways you can help, from reviewing articles to be sure they make sense, to contributing text, to adding sample code. In fact, there are so many ways to help that we have an actual tool to help you pick tasks to help, based on your interests and how much time you have to spare!

The MDN community

Our community is a global one! We have amazing contributors all around the world, in a number of languages. If you'd like to learn more about us, or if you need help of any kind with MDN, feel free to check out our mailing list or IRC channel !

Join the MDN community

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Choose your preferred method for joining the discussion.

Copyrights and licenses

MDN wiki documents have been prepared with the contributions of many authors, both within and outside the Mozilla Foundation. Unless otherwise indicated, the content is available under the terms of the Creative Commons Attribution-ShareAlike license (CC-BY-SA), v2.5 or any later version. Please attribute "Mozilla Contributors" and include a hyperlink (online) or URL (in print) to the specific wiki page for the content being sourced. For example, to provide attribution for this article, you can write:

About MDN by Mozilla Contributors is licensed under CC-BY-SA 2.5.

Note that in the example, "Mozilla Contributors" links to the history of the cited page. See Best practices for attribution for further explanation.

Note: See MDN content on WebPlatform.org for information about how to reuse and attribute MDN content on that site.

Code samples added to this wiki before August 20, 2010 are available under the MIT license; you should insert the following attribution information into the MIT template: "© <date of last wiki page revision> <name of person who put it in the wiki>".

Code samples added on or after August 20, 2010 are in the public domain. No licensing notice is necessary, but if you need one, you can use: "Any copyright is dedicated to the Public Domain. https://creativecommons.org/publicdomain/zero/1.0/".

If you wish to contribute to this wiki, you must make your documentation available under the Attribution-ShareAlike license (or occasionally an alternative license already specified by the page you are editing), and your code samples available under Creative Commons CC-0 (a Public Domain dedication). Adding to this wiki means you agree that your contributions will be made available under those licenses.

Some older content was made available under a license other than the licenses noted above; these are indicated at the bottom of each page by way of an Alternate License Block.

Important: No new pages may be created using alternate licenses.

Copyright for contributed materials remains with the author unless the author assigns it to someone else.

If you have any questions or concerns about anything discussed here, please contact Eric Shepherd.


The rights in the trademarks, logos, service marks of the Mozilla Foundation, as well as the look and feel of this web site, are not licensed under the Creative Commons license, and to the extent they are works of authorship (like logos and graphic design), they are not included in the work that is licensed under those terms. If you use the text of documents, and wish to also use any of these rights, or if you have any other questions about complying with our licensing terms for this collection, you should contact the Mozilla Foundation here: [email protected].

Download content

You can retrieve the content of a single page on MDN by adding document parameters to the URL to specify what format you want.

If you want to download a complete, anonymized SQL dump of the MDN database -- that is, a copy of the database with all private user information scrubbed out, we provide that as well. This dump is updated on the first day of each month.

There are three archives that comprise the anonymized monthly dump of MDN:

<date>.sanitized.devmo_sanitize.sql.gz
The sanitized MySQL database dump of all of MDN's content, data records, and so forth. This is all article content, history records, and so forth. All personal user information has been stripped out (such as email addresses).
attachments-<date>.tar.gz
This archive contains all the file attachments that have been uploaded to the wiki.
uploads-<date>.tar.gz
This (very large!) archive contains the files uploaded to the Demo Studio. If your interest is only in wiki content, you don't need to download this.

Visit the MDN landfill to download these files.

Third-party tools

You can also view MDN content via third-party tools like Dash (for Mac OS) and Zeal (for Linux and Windows).

Reporting problems with MDN

Now and then, you may run into problems while using MDN. Whether it's a problem with site infrastructure or an error in documentation content, you can either try to fix it yourself or report the problem. While the former is preferred, the latter is sometimes the best you can manage, and that's okay too.

Documentation errors

Obviously, since MDN is a wiki, the best thing you can possibly do is fix problems you spot yourself. But maybe you don't know the answer or are in the middle of rushing to the hospital or something, and need to jot down the problem so someone can look at it later.

As is the case with all things Mozilla, you report a documentation problem by filing a bug. That's when filing a documentation request bug comes in. Our handy documentation request form will gather the information needed to get us started on fixing the issue.

Of course, our writing community is busy, so sometimes the quickest way to see a documentation problem resolved is to fix it yourself. See Creating and editing pages for details.

Site bugs or feature requests

Kuma, the Mozilla-developed platform used for the MDN web site, is in a state of continuous development. Our developers—as well as a number of volunteer contributors—are constantly making improvements. If you see a bug, or have a problem with the site, or even have a suggestion for something that could make the software more awesome, you can use the Kuma bug form to file a report.

History of MDN

The Mozilla Developer Network (a.k.a. Mozilla Developer Center (MDC), a.k.a. Devmo) project started in early 2005, when the Mozilla Foundation obtained a license from AOL to use the original DevEdge content. The DevEdge content was mined for still-useful material, which was then migrated by volunteers into this wiki so it would be easier to update and maintain.

Since then, the project has continued growing and now forms a central nexus for all developer documentation related to the Mozilla Project and open web technologies. In 2010, the name was changed to Mozilla Developer Network; 2011 saw the addition of Demo Studio for web developers to share and show off their code, and Learning pages to provide links to tutorials. (The name MDC lives on as "MDN Doc Center" for the documentation section.) In time, it is hoped that the Mozilla Developer Network will become a resource that web designers, application developers, and extension and theme writers visit on a regular basis.

About Mozilla

Whether you want to learn more about who we are, how to be a part of Mozilla or just where to find us, you've come to the right place. To find out what drives us and makes us different, please visit our mission page.

Document Tags and Contributors

 Contributors to this page: Lungv
 Last updated by: Lungv,