OStatic

Opera, though it's a fine browser, is closed-source - which is one reason why most open source advocates are still running Firefox as their preferred way to access the web. But a new tool from Opera, named Dragonfly, is open source (code under a BSD license). If you do web development, it might tempt you to fire up an Opera session from time to time.

Opera pitches Dragonfly as a tool for debugging web pages and web applications. Its feature set includes a JavaScript error console and command line, a debugger, and CSS and DOM inspectors. The current release (out today, and requiring Opera 9.5 beta 2) is an alpha, but they've announced planned improvements for the future. Notably, write access to CSS and DOM properties is still to come, as well as support for non-desktop versions of Opera.

The immediate and obvious comparison is with Firebug, the debugging add-in for Firefox. Frankly, right now Firebug is way ahead on functionality. So why even look at Dragonfly? Three reasons. First, Dragonfly is built to support remote debugging with other Opera sessions, even on other machines or devices; this will be especially useful for non-PC devices. Second, the remoting protocol will be published, meaning you could conceivably instrument Firefox to be debugged via Dragonfly. Third, if you're trying to chase bugs that appear only in Opera (or trying to understand rendering differences between Opera and other browsers) it offers you a native way to dig into Opera sessions.

Today's release is an alpha, and it still has a ways to go. But given Opera's long-term tenacity in the browser world, it belongs on your radar.

• opera
• dragonfly