Drop Down Panel script 介绍
Drop Down Panel adds a pull down panel to the top of your page that contains
external content fetched via Ajax. Visitors click on the protruding button to
cause the panel to drop down and reveal its content. Clicking anywhere on the
panel again closes it. You can easily customize the height of the Panel,
button text (ie: “panel content”), and drop down speed in milliseconds. A plug
and play Ajax drop down panel!
使用方法请看：
http://www.javascriptkit.com/script/script2/dropdownpanel.shtml