This refers to that search drop down box at the top right of Firefox 2.0. The 1.x version is different, so this will only work if you have 2.x.
This will provide a google site search within the Firefox browser.
As you can see, the image is base64 encoded. You can use
this site to encode your image. I used a transparent gif.
Code:
<SearchPlugin xmlns="http://www.mozilla.org/2006/browser/search/">
<ShortName>Code Newbie</ShortName>
<Description>Code Newbie Site Search</Description>
<InputEncoding>UTF-8</InputEncoding>
<Image width="16" height="16">data:image/x-icon;base64,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</Image>
<Url type="text/html" method="GET" template="http://www.google.com/search">
<Param name="q" value="{searchTerms}"/>
<Param name="sitesearch" value="codenewbie.com"/>
</Url>
<SearchForm>http://google.com/</SearchForm>
</SearchPlugin> Name that file
whatever.xml and drop it in your
Mozilla Firefox/searchplugins/ directory.