search tags like stackoverflow? [duplicate]

This question already has answers here: jQuery autocomplete tagging plug-in like StackOverflow's input tags? [closed] (6 answers) Closed 9 years ago.

how do you code a search box like the one in Tags where you enter a tag name and all tags are showing immidiately without you press enter.

can someone link me a script or tutorial for that. is it javascript or jquery? doe开发者_开发问答s it involve ajax?

and does it search in the database for tags? or is it searching through a xml file with tags?

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Check out this JS library, http://harvesthq.github.com/chosen/