Suppose you are browsing http://www.wired.com and you want to search for an article on "Firefox" on the site.
You scroll up/down the webpage, locate the search field, set focus on it and enter/submit your query. On some sites such as http://www.animesuki.com you even need to do a "mouse-over" first to display the HTML search field. Every website is designed differently and its search field, if any, positionned and accessible differently as well.
If you use the "SearchThisSite" addon instead, you just access it quickly with your mouse (keyboard shortcut: ALT+Q for the power users) and enter/submit your query. Et voilà!
In the end, both methods will lead you to: "http://www.wired.com/search?query=Firefox&siteAlias=all" but using the "SearchThisSite" addon is definitely less time-consuming.
HOW DOES IT WORK?
Firefox provides a "way to search specific websites directly from the Firefox Location bar" called "Smart keywords". See: http://support.mozilla.com/en-US/kb/Smart+keywords for details.
Based on this, the "SearchThisSite" searchbar works by determining the search field and the search URL for the page (in our example: http://www.wired.com/search?query=%s&siteAlias=all). Upon submitting, the addon replaces "%s" by the query string (in our example: "Firefox").
Note that the addon supports both GET and POST forms.
MAJOR CHANGE SINCE VERSION 0.2
WHY USE THE INTERNAL SEARCH ENGINE INSTEAD OF AN EXTERNAL ONE?
- access to the latest results
- access to private sections of the website (forums, etc...), not accessible to extenal search engines
- privacy: you do not wish to share information with an external search engine.
To install (in Firefox only):
1) right-click your toolbar and click "Customize"
2) locate the "SearchThisSite" addon and drag/drop it to the toolbar
3) click "Done"