I recently replaced the search box for EmacsWiki with a Google Custom Search Engine. This is better than adding the `site:emacswiki.org` term because `emacswiki.org/cgi-bin/emacs` and `emacswiki.org/cgi-bin/alex` are two different sites. It is possible two create two different search engines and supply the appropriate URL patterns, and it seems to work.
Here’s a possible setup for your config file. Note how I removed the submit button and the fancy Javascript, and I deleted the id attribute for the form (because this form will appear at the top and at the bottom of every page). Also note the ugly hack of closing the span, printing a form, and opening a new span to have this all fit into a normal goto bar. Uuuugly. But it works. 😄
$UserGotoBar = qq{</span>
<!-- Google CSE Search Box Begins -->
<form class="tiny" action="http://www.google.com/cse"><p>
Google:
<input type="hidden" name="cx" value="004774160799092323420:s9wlu0va1v0" />
<input type="text" name="q" size="25" />
</p></form>
<!-- Google CSE Search Box Ends -->
<span>
};
#Oddmuse #Google #Search