javascript and therefore jquery can ONLY "search" the document that it is running on/in. To search documents on the server requires server side code.
You can implement a Google "site search" but that will only search documents/URLs that are already indexed by Google.
Failing that take a look at FreeFind the cost of the "free" version is adverts on the results pages.
Sorry, should have mentioned it was a 'site' search i was referring to not web search.