acts_as_taggable_on with finders

I would like to use acts_as_taggable_on to do a auto suggest style tagging similar to stackoverflow below... that or facebook.

But I'm unsure looking thru the rdocs what methods to use to pull all the various tags from a giving model.

Article.tag_counts_on(:tags)

That gives me all the tags... but i'd like to do something more advanced with a finder.. ie they start typing and i narrow the search... I'm sure this must have been done, so before I start reinventing the wh开发者_如何学Goeel and using the tag model directly could someone point me in the right direction?

Also... is there an easy way to limit the number of tags they can enter? I used

validates_presence_of :tag_list

To validate the tags, but what about limiting them to 5? Any easier way than using a validation to count commas? I would figure this quite common.

I found this style of autocomplete tagging: link text

but i really like stackoverflow's functionality more... anyone know of any other good autocomplete jquery solutions?

Thanks

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Check out the jquery plugin called autocomplete

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If you're willing to setup your results in JSON, then loopj's jQuery Tokenizing Autocomplete might be just the right jQuery plugin for you. For more examples, see the website or the demo.