Welcome to Opera Dragonfly alpha, the foundations of Opera's upcoming Developer Tools. Debug JavaScript, inspect CSS and the DOM, and view any errors – Opera Dragonfly makes developing using Opera easier than ever, both on your computer and mobile phone. Check out our alpha release for a taste of things to come.
Reach breaking point step by step
Opera Dragonfly's fully featured JavaScript debugger makes building sophisticated Ajax applications easier than ever. Step through your code line by line, setting break points along the way. This allows you to make sure your application and scripts are acting as you designed them.
Redefine your style
Its not just the DOM you can inspect. Check out what CSS rules apply to which element, and what rules are inherited or set by browser defaults. Overridden rules are highlighted so you can see what styles are or aren't applied. Support for editing CSS rules will be added in an upcoming version.
Think open and free
Built using the open web standards you know and love, Opera Dragonfly’s source is available to view. Not only that, but it is released on a open source BSD license, meaning it is free as in freedom and well as in beer.
Always up to date
Opera Dragonfly is a new breed of hybrid application. Part desktop application, part web application, it resides in local persistent storage, yet instantly updates when a new version is released – just like your favorite web sites*. You never have to check for updates or install a new version.
Spot your errors
An improved error console allows you to see, filter and log any errors in your scripts, pointing to the exact position the error occurred. Use this in combination with the other tools to hunt down and fix your site’s bugs.
Debug the DOM
View source isn’t much use if you use DOM Scripting to alter the DOM. Opera Dragonfly allows you to inspect the updated DOM and all its properties. Support for editing the DOM will be added in an upcoming version.
Debug your phone or TV
Debug pages whether they are on your computer or a supported device, such as a Windows Mobile phone running Opera Mobile 9.5. You can connect to any device running Presto Core-2.1 or above, and debug using your computer’s screen and keyboard – No need to struggle inputting test data with your phone’s keypad again.
Coming soon
The initial alpha release is just the beginning. Opera Dragonfly has a fully featured road map, including support for editing of CSS, JavaScript and the DOM, a single window mode, improved JavaScript thread handling, XHR and HTTP monitoring, improved keyboard navigation, and translation into a number of languages.
Download Source
Opera Dragonfly - Take a peek into the future 
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