Firefox 2 for developers

New developer features in Firefox 2

Firefox 2 introduces a vast array of new features and capabilities. This article provides links to articles covering the new features.

For website and application developers


Microsummaries are regularly-updated succinct compilations of the most important information on web pages. Site and third-party developers can both provide them, and users can choose to display microsummaries instead of static titles when they bookmark pages with microsummaries.

Creating a Microsummary

A tutorial on creating a microsummary generator.

Microsummary XML grammar reference

A reference guide to the XML grammar used for creating microsummary generators.

Creating OpenSearch plugins for Firefox

Firefox 2 supports the OpenSearch search engine format.

Creating MozSearch plugins

Firefox 2 supports MozSearch, a search plugin format based on OpenSearch, but intended only for internal use.

Supporting search suggestions in search plugins

How to make your MozSearch plugin support search suggestions, which appear in a drop-down list while typing in the search bar.

New in JavaScript 1.7

Firefox 2 supports JavaScript 1.7, which includes new features including let, destructuring assignment, generators and iterators, and array comprehensions.

WHATWG Client-side session and persistent storage (aka DOM Storage)

Client-side session and persistent storage allows web applications to store structured data on the client side.

SVG in Firefox

Firefox 2 improves Scalable Vector Graphics (SVG) support, implementing the <textPath> element and adding support for some attributes not previously supported.

Controlling spell checking in HTML forms

Firefox 2 includes support for inline spell checking in text areas and text fields. This article describes how to write your HTML to enable and disable spell checking on individual form elements.

Security in Firefox 2

Firefox 2 has changes to which security protocols are enabled by default.

For XUL and extension developers

Updating extensions for Firefox 2

Covers how to get your existing extensions to work with Firefox 2.

Session store API

Contributing items to be saved and restored across sessions in Firefox.

Feed content access API

API that lets developers access and parse RSS and Atom feeds.

SAX support

Event-based XML parser API.

Adding search engines from web pages

JavaScript code can instruct Firefox to install a new search engine plugin, which can be written using either OpenSearch or Sherlock format.

Using spell checking in XUL

How to check the spelling of words or get a list of suggested spellings from code.

Adding phishing protection data providers

It's possible to enhance Firefox's phishing protection by adding additional data providers for the safe browsing system.

Adding feed readers to Firefox

You can add new feed readers to Firefox, whether web-based or application-based.


Firefox 2 introduces mozStorage, an sqlite based database architecture.

Theme changes in Firefox 2

Discusses the changes needed to update existing themes to work in Firefox 2.

Textbox Improvements (Firefox and higher only)

The <textbox> now has a reset() method to reset the value of the textbox to the default value. The defaultValue property may be used to retrieve and modify the default value of the textbox (Firefox bug 312867). Supports an editor property to get the internal nsIEditor for the text field (Webkit bug 312867).

New features for end users

Firefox 2 provides an enhanced version of the same clean user interface offered by previous versions, with improved security features to make your online experience safer and more convenient than ever.

User experience

  • Inline spell checking for text areas lets you compose with confidence in web forms.
  • Microsummaries provide a way to create bookmarks that display information pulled from the site they refer to, updated automatically. Great for stock tickers, auction monitoring, and so forth.
  • Extension Manager user interface has been enhanced.
  • Search engine manager lets you rearrange and remove search engines shown in the search bar.
  • Tabbed browsing enhancements include adding close buttons to each tab, adjustments to how Firefox decides which tab to bring you to when you close the current tab, and simplified preferences for tabs.
  • Autodetection of search engines allows search engines that offer plugins for the Firefox search bar to offer to install their plugins for you.
  • Search suggestions allow search engines to offer suggested search terms based on what you've typed so far in the search bar.

Security and privacy

  • Phishing Protection to warn users when the website you're looking at appears to be a forgery.

See also