Opera Software
  1. Toolbars
  2. Menus
  3. Panels
  4. Speed Dial
  6. Extensions
  7. Opera Widgets
  8. Notes
  9. Geolocation
  10. Opera Link
  11. Opera Turbo
  12. Opera Unite
  13. Content blocking
  14. Fraud and Malware Protection
  15. BitTorrent
  16. Display modes
  17. Developer tools
  18. Preferences
  19. Advanced Preferences
  20. Skins
  21. Keyboard shortcuts
  22. Using the mouse
  23. Email and news
  24. Feeds
  25. Chat
  26. Dialogs
  27. Auto-update
  28. Backing up Opera

Developer tools

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What developer tools are provided by Opera?

Opera includes several tools to aid web developers:

See also Opera Developer Tools.

What is Opera Next?

Opera Next is a parallel build of Opera, with cutting-edge features. It is useful especially to developers and testers. You can install it and run it independently of your primary version of Opera; the two do not mix. To avoid confusion, Opera and Opera Next are distinguishable by their appearance:

but it is the difference in behavior that truly distinguishes Opera Next:

By default, Opera Next is auto-updated every time a new snapshot appears on the Opera Desktop Team blog, including all of the alphas and betas released by Opera. To slow down the release cycle, so that you only get alphas and betas, but not all the snapshots from the Opera Desktop Team, unselect the option DownloadAllSnapshots, and save the setting.

Snapshot Alpha Snapshot Beta Snapshot RC Final
Opera Next (with snapshots) X X X X X X X
Opera Next (no snapshots) X X X
Opera X

For stable day-to-day browsing, use Opera; to experiment with the latest and greatest features, use Opera Next.

What is Opera Dragonfly?

Opera Dragonfly is a tool for developing and debugging local and remote webpages. It includes a DOM view of webpages and highlighting of elements. You can step through your JavaScript code, and quickly inspect changes to your CSS styles. You can debug your extensions and widgets, and study your application's impact on network resources.

One of the standout features of Opera Dragonfly is remote debugging. Remote debugging makes it possible to debug webpages as seen on a mobile phone or a television from your desktop.

The complete list of features in Opera Dragonfly is too long to detail here. For more information, see the following pages:

Opera Dragonfly is implemented as a web application, and updates occur automatically as soon as they are posted to the server. The application is open source, with an Apache 2.0 license.

How do I open Opera Dragonfly?

To open Opera Dragonfly, take one of the following steps:

How do I close Opera Dragonfly?

To close Opera Dragonfly, take one of the following steps:

What is the error console?

The error console reports errors that Opera encounters while rendering webpages. To avoid confusion, it is necessary to distinguish between two similar features:

In Opera: The error console
From the Opera main menu, select View > Developer Tools > Error Console.
In Opera Dragonfly: The Errors panel
In Opera Dragonfly, select the Errors panel

In summary, the difference is that the Errors panel in Opera Dragonfly provides better context, but it only begins reporting errors after Opera Dragonfly is opened, while Opera's error console is the better choice when you require complete error reporting from the time that the browser is first opened.

What is the source viewer?

The source viewer is a simple tool for analyzing and modifying webpages. If you want to have a look at the source code of the current webpage, take one of the following steps:

The source viewer opens in a new tab on your tab bar, and it has syntax highlighting to give you a better overview of the source. It is not just a viewer, but also an editor, and allows you to make changes to the page. It may surprise you to learn that you can make changes to the page (temporarily), even if it is not on your computer! If the page is on your computer, changes to the page are applied permanently. If not, changes to the page are applied only in cache, and reloading the page will reset it to its original state.

The source viewer includes two buttons for modifying and saving the page:

If you prefer to use an external program for source viewing and editing, you can specify it in the programs preferences.