Rtd-shortcuts is a project mainly written in JavaScript, it's free.
Keyboard shortcuts for browsing documentation on readthedocs.org using greasemonkey
.. |maintenance status| image:: http://stillmaintained.com/Geekfish/rtd-shortcuts.png
Simple greasemonkey reading-helper script for readthedocs.org.
Install the latest version of greasemonkey from https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/
Open the script in firefox or simply drag and drop it on any open tab.
"n" or "right arrow" next page "p" or "left arrow" previous page "i" index "f" go to search
Greasemonkey development wiki: http://wiki.greasespot.net/