In Firefox, pressing the "Space" key in a webpage usually makes it scroll down one page (page down) until the end of the page is reached.
Opera browser has the same behaviour, except that at the end of the page, the next page is automatically loaded (with more or less success), thanks to the "Fast Forward" function.
This addon tries to replicate Opera's ability to automatically load the next page, hopefully, more successfully results-wise.
It works "out of the box" and requires no additional rules/parameters. An "append" mode is also available.
Google, Yahoo, Bing, Picasa, Flickr Search with   ...
1) HTML element [link rel="next"...]
2) HTML elements [a rel="next"...] and [area rel="next"...]
3) numerical sequences   ...
4) textual keywords such as "Next", "Next Page", "Older Stories", etc... (in English and French only for the time being)
Please note that the addon works with HTML elements only (no Flash, Java, Silverlight, etc...)
An "Options" window has been introduced in version 0.23. Help is available as tooltip on each element.
To install the toolbar icon (optional):
1) right-click your toolbar and click "Customize" (or go to: View/Toolbars/Customize...)
2) locate the "Space Next" icon and drag/drop it to the toolbar
3) click "Done"
IMPORTANT NOTE (December 2016)
Space Next is not and will not be made compatible with Electrolysis (aka Multi-Process Firefox or e10s). Sorry for the inconvenience. You may try disabling Electrolysis to use the addon if needed (see Enable / Disable Electrolysis in Firefox). Thank you for your understanding.