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解决方案 »

  1.   

    第一个FOR,所有的UI都不可见,第二个FOR,如果是当前鼠标指向的UI可见。
      

  2.   

    2个for是初始化操作,遍历所有UL,设为隐藏;遍历所有LI初始化样式
    后2句,是设置当前鼠标移动到的LI样式以及显示相应的UL
      

  3.   

    两个for 把对应的ul设置为隐藏,并把ul的样式清空后面则设置当前的UL的样式,让其显示
      

  4.   

    两个for是让所有UL初始化为隐藏;初始化所有LI样式 .后面的是设置鼠标事件.楼主的钻研精神很好!