<select></select> boxes can be rather unwieldy and don’t exactly cater for a stellar user-experience. To alleviate that pain Harvest provide a highly useful jQuery plugin that’s been adequately named Chosen.
Apart from a nice CSS styling Chosen adds several user interface improvements to vanilla HTML select boxes such as search, easy-to-use multiple selections and option groups.
This will automatically spruce up and enrich every select box on your website and really once you’ve tried Chosen there’s no going back again to default HTML select boxes.
The source code for Chosen is available here.