If you are not aware of what ‘userscripts’ are or what ‘Greasemonkey’ is then perhaps you must first see this page: http://en.wikipedia.org/wiki/Greasemonkey
1. If you are using Seamonkey ,you can run userscripts using ‘Scriptish’ add-on: https://addons.mozilla.org/en-US/firefox/addon/scriptish/
2. If you are using Google Chrome you can use ‘Tampermonkey’ extension: https://chrome.google.com/webstore/detail/tampermonkey/
3. Mac Users who are using ‘Safari’ can use Greasekit. You can find more informtion here: http://8-p.info/greasekit/
4. Older version of Opera users can use ‘Violentmonkey’ : https://addons.opera.com/en/extensions/details/violent-monkey/
Here are some of the most useful Scripts you can install for Greasemonkey/Tampermonkey:
#1. Anti-Adblock Killer: Disables Anti-Adblock scripts. Allows you keep using “Adblock Plus” or similar add-on/extensions on websites those are trying to enforce Anti-Adblock mechanism (i.e In simpler terms trying to force you to view the ads !).
=> Install Link: http://userscripts.org/scripts/show/155840
2. Google Image Enhancer: Enhances and ease the use of Google Image Search. Create Direct Links to Result Images. Changes the Image Search to basic mode.
=> Install Link: http://userscripts.org/scripts/show/150950
#Alternative : Google Image Direct Link: http://userscripts.org/scripts/show/78355 (Creates direct link to ‘Google Image Search’ Result Images)
#Google Image Enhancer in Action:
3. Webcomic Reader: Preloads 5 or more pages ahead (or behind). Allows you to navigate via keyboard arrow keys. Allows to shrink images or expand them to fit the browser window.
Allows you to save settings on per Site basis etc.
=> Install Link: http://userscripts.org/scripts/show/59842
4. Youtube Center: Allows you to set the default video playback quality. Prevents auto-play. Allows pre-bufferring. Centers the video. Allows you to download the video. Forces html5 over Flash player etc. This is a prefect alternative of “Magic Actions for YouTube” addon/extension. For “Seamonkey and older version of Opera” this is the Script you must install first before visiting YouTube.
#Youtube Center in Action:
5. AES Shortcut: Allows you encrypt/decrypt text using password. If all you need to encrypt a email message so that no one else without the password could read it, then its the best and the simplest.
=> Install Link: https://userscripts.org/scripts/show/52357
6. Google Books Downloader: Allows you to download Books from http://books.google.com
=> Install Link: http://userscripts.org/scripts/show/37933
#Google Book Downloader in Action:
7. Inline Mp3 Player: Adds a tiny flash based player after all publicly available available .mp3 direct links to allow you to play the Audio without downloading. Specially useful if you are on Linux and dont want to install Gstreamer Plugins.
#Inline mp3 Player and Player button in Action: