I finally found an explanation about chrome at http://www.chromium.org/tab-to-search
Basically, you need to link an OpenSearch description document.
<head> <link type="application/opensearchdescription+xml" rel="search" href="url_of_osdd_file"/> </head>
And this is the osdd file:
<?xml version="1.0"?> <OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/"> <ShortName>Search My Site</ShortName> <Description>Search My Site</Description> <Url type="text/html" method="get" template="http://my_site/{searchTerms}"/> </OpenSearchDescription>
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