Opera

To view the source of a document, press Ctrl+F3. To view the source of a single frame, you can press Alt+F3, but it's often easier to make sure you have the right frame by right-clicking and choosing Frame > Source.

External viewers

If you prefer to view the source in an external program, such as the text editor of your choice, you can configure Opera to use it instead of the internal viewer. To set it up, go to Tools > Preferences > Advanced > Programs, and click the Edit button below "Choose application for viewing source". The next time you view the source of a document or a frame, it will appear in the external application that you chose.

If you are having problems, try the following:

• Sometimes you need to specify the full path to the program, such as C:\WINDOWS\system32\NOTEPAD.EXE (Windows) or /usr/bin/emacs (Unix/Linux).
• On Linux, you may find that some viewers or editors need to run inside a terminal. Try checking the "Open in terminal" check box.

For web developers: editing source on the fly

The source window is not only for viewing the source. It can also be used for editing Opera's local copy of the current web page. If you want to experiment quickly with a web page without having to upload it to a server every time you test something, you can do the changes inside Opera's source tab. When you are ready to test a change, click the "Apply changes" button, and switch to the tab with the web page in it. If something didn't work the way you expected, you can change it again. If you want to start over, you can reload the page and open a new source window.

It is even possible to use an external editor for this, but doing so is slightly more complicated.

1. Set up the external editor as described above, if you have not already done so.
2. In the editor, edit the source of the web page, and save it, as you would with any other file.
3. In Opera, go to Tools > Advanced > Reload from cache.