These extensions are completely unofficial and utterly unsupported. I can't guarantee the results are the same, or as good, as going to the official documentation sites either, this is just a convenience method for people who end up searching against them frequently.
- Force.com Apex Documentation Search
Allows you to search against Apex Documentation by typing 'apex' in the Chrome Omnibox (Location Bar), then either tab or space, then a search term. Download.
<LI><B>Force.com Visualforce Documentation Search</B>
<P>Allows you to search against <a href="http://www.salesforce.com/us/developer/docs/pages/index.htm">Visualforce Documentation</a> by typing 'vf' in the Chrome Omnibox (Location Bar), then either tab or space, then a search term.
<a href="FDC-VF-Search.crx">Download</a>.
</P>
</LI>
<LI><B>Force.com API Documentation Search</B>
<P>Allows you to search against <a href="http://www.salesforce.com/us/developer/docs/api/index.htm">API Documentation</a> by typing 'api' in the Chrome Omnibox (Location Bar), then either tab or space, then a search term.
<a href="FDC-API-Search.crx">Download</a>.
</P>
</LI>