这是一个既简单又酷的菜单条，采用javascr ipt语言来制作，比较有特色，可以好好看看！通过定义清空各菜单的函数、菜单展开的函数等函数来编写-This is a simple menu of cool, using javascr ipt language to produce, more features and a good look! By definition emptied the menu function, a fun