Opera betas open source web debugger

Opera has released the first official beta version of Dragonfly, its open source debug tool for web developers.

Similar to Mozilla's Firebug tool, Dragonfly debugs JavaScript, CSS, DOM, and HTML code, and it supports newer web technologies such as SVG and various HTML5 APIs. The tool includes a network inspector that lets you see what resources an application loads in what order and look, and there's a storage inspector that lets you update and test cookies and the HTML5 web storage API.

It can also remotely connect to non-PC devices running version Opera's Presto rendering engine. So you can, for instance, use your desktop browser to debug a site running on Opera Mobile.

Dragonfly is the Norwegian browser maker's first open source project. The code has been open since the project's inception in 2008, carrying a BSD license, and last May, after moving from Opera's server to BitBucket, it switched to an Apache license in order to provide added patent protection to users.

The tool only works with the Opera browser. When you download the browser, the debug tool loads automatically from the web. It speaks to the browser via Opera's Scope protocol, which has also been open sourced under an Apache 2.0 license.

It's called Dragonfly because, yes, it eats bugs. "That is exactly what we want it to do for developers around the world," reads a canned statement from David Storey Opera's Chief Web Opener. "You spend your time making the web better for everyone. The least we can do is make life easier for you.”

To enable Dragonfly in Opera, enter "opera:config#DeveloperTools|DeveloperToolsURL" into your the browser's address bar, change “DeveloperToolsURL” to https://dragonfly.opera.com/app/cutting-edge, and click "save". You can then open Dragonfly via a Ctrl+Shift+I shortcut on Windows and Linux or ⌘+⌥+I on Macs. ®