http://users.tpg.com.au/j_birch/plugins/superfish/#
http://designreviver.com/wp-content/uploads/2008/10/example.html
http://www.kriesi.at/wp-content/extra_data/suckerfish_tutorial/step4.html#
http://uvumitools.com/dropdown.html
http://greengeckodesign.com/projects/MenuMatic/examples/vertical/index.htm?q=projects/menumatic/examples/vertical/
横向菜单