搜索像stackoverflow这样的标签？ [重复]

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                        <a href="/questions/519107/jquery-autocomplete-tagging-plug-in-like-stackoverflows-input-tags" dir="ltr">jQuery autocomplete tagging plug-in like StackOverflow's input tags? [closed]</a>
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                                (6 answers)
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            <div class="grid--cell mb0 mt8">Closed <span title="2013-07-22 02:26:58Z" class="relativetime">6 years ago</span>.</div>
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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? does 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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