Google Allows Developers Integrate With Search Result within Site Feature
Google announced a few changes to the search box you find within the Google search results. Often, when you search for a brand name, Google will add a search box within the search snippet result for that site. That box allows you to search within that specific site only.
The results are similar to the site command Google allows users to use when searching a specific domain only.
The few updates include
(1) Moving the search box above the site links in the snippet
(2) Adding auto-complete results to the search results in that box and
(3) Enabled developers to instruct Google to send the search results directly to their own site.
Here is a picture of the new interface: