BDC DrillDown Menu (iPod-style Menu) 介绍
The BDC DrillDown Menu is a compact, hierarchical menu implemented as a jQuery
plugin. A drilldown menu takes up constant space like an accordian menu but
offers the deep hierarchy of a flyout menu at the same time. The BDC DrillDown
Menu turns a standard HTML list into a dynamic JavaScript drilldown menu that
maintains a small profile no matter how deep the hierarchy it controls. This
is quite similar (though with more features) to the menu used in the iPod.