说明：  有一种按键，看起来是一幅完整的图片，当鼠标移到按键区域时，图片的一部分凸现，形成一个按键，当鼠标移走时又恢复原来状态。
(a button, and seemed to be a complete picture, when moving the mouse button areas, Photo part of the highlights, forming a button when the mouse is removed when the restoration of the status quo ante.)