Notably, Firefox 2 Beta 1 has built-in phishing protection, which turns on by default and checks sites that users browse against a local list of known phishing sites.

The new beta also boasts better support for previewing and subscribing to RSS feeds, inline spell-checking, new micro-summaries feature for bookmarks and automatic restoration of a browsing session.

Also, Mozilla has added changes to tabbed browsing behavior, so new browser windows now open in tabs by default. And search suggestions now appear with search history in the search box for Google, Yahoo and Answers.com. A new search plugin manager has been added for removing and re-ordering search engines. There also is a new combined Add-Ons manager for extensions and themes.

Under the hood, Mozilla has introduced better support for JavaScript 1.7, extended search plugin format, and updated the extension system. It also has boosted support for client-side session and persistent storage, as well as support for SVG text using svg:textPath. Also, the beta has a new Windows installer.

Firefox 2 Beta 1 is aimed at Web application developers and should not be used by Firefox 1.x users, Mozilla said.