The Mozilla Foundation has released a test preview of the next version of the Firefox browser, showing off the upcoming release's improved pop-up blocking, enhanced navigation and added support for Web standards.

Mozilla Firefox 1.5 Release Candidate 1 is available now from the Mozilla Foundation so that testers can make any last-minute fixes before the final code is released.

The foundation also warns in a statement on its site that the release is for testing purposes only without end-user support. Users who do not wish to download it for that purpose should continue to rely on the current version of the browser, Firefox 1.0.

Firefox 1.5 should be available in full release before the end of the year, with one more preview to be made available as early as November 11 if feedback from Release Candidate 1 is positive, according to the Mozilla Web site.

New Features

New features in the browser include a better system for updating software, faster navigation using the "Back" and "Forward" tabs, and a redesigned Options/Preferences window that increases the number of category icons and moves them from the left side of the window to the top.

Firefox 1.5 also includes new support for Web standards, adding support for Scalable Vector Graphics (SVG), JavaScript 1.6 and CSS (Cascading Style Sheets). SVG is an XML-based language for writing sophisticated two-dimensional graphics, and JavaScript 1.6 is the latest versions of the Java scripting language. CSS is a World Wide Web Consortium (W3C) standard for adding style, such as fonts, colors and spacing, to Web documents.

In addition, Firefox 1.5 adds improved Dynamic Hypertext Markup Language (DHTML) accessibility features and better support for Mac OS X. DHTML is an extension of HTML that uses JavaScript and style sheets to enable the inclusion of small animations and dynamic menus in Web pages.

Firefox has become an increasingly popular alternative to Microsoft's Internet Explorer browser. In October, downloads of Firefox topped 100 million.