参考：http://www.w3school.com.cn/tiy/t.asp?f=csse_zindex
cursor 属性规定要显示的光标的类型（形状）。
<html> <body> <p>请把鼠标移动到单词上，可以看到鼠标指针发生变化：</p> <span style="cursor:auto"> Auto</span><br /> <span style="cursor:crosshair"> Crosshair</span><br /> <span style="cursor:default"> Default</span><br /> <span style="cursor:pointer"> Pointer</span><br /> <span style="cursor:move"> Move</span><br /> <span style="cursor:e-resize"> e-resize</span><br /> <span style="cursor:ne-resize"> ne-resize</span><br /> <span style="cursor:nw-resize"> nw-resize</span><br /> <span style="cursor:n-resize"> n-resize</span><br /> <span style="cursor:se-resize"> se-resize</span><br /> <span style="cursor:sw-resize"> sw-resize</span><br /> <span style="cursor:s-resize"> s-resize</span><br /> <span style="cursor:w-resize"> w-resize</span><br /> <span style="cursor:text"> text</span><br /> <span style="cursor:wait"> wait</span><br /> <span style="cursor:help"> help</span> </body> </html>