I am not able to search using the Google Custom Search field on docs.ansible.com in either Firefox (43) or Chrome (47). To be more specific, the URL loads with the search terms, but the search results do not appear on the page. The page remains the original Welcome to Ansible documentation page.
There is a bug in github that is marked closed/fixed, but as a number of people have already commented, it isn’t fixed and is really annoying.
John