Is it possible to have a search-as-you-type functionality for the search box in the upper right?

Currently if you search for something and don't find it on the first try you have to go back and forth from the search page to the result page, kinda annoying.
Of course there should be still an advanced search page, where you could tweak your search.

I'm pretty sure I have already seen such functionality in a (phpBB?) forum, but I can't find it now but ask.libreoffice.org is also an example.