点击右键看看！
onmousedown="down=true;divleft=event.clientX-parseInt(plane.style.left);
divtop=event.clientY-parseInt(plane.style.top)" onmouseup="down=false">
onmouseover="menuin();init()">右键菜单
onmouseout="this.className='none';" class="none"
>网络学院
class=none onmouseover="this.className='over';menuin()"
onmouseout="this.className='none';">菜单项二
class=none onmouseover="this.className='over';menuin()"
onmouseout="this.className='none';">菜单项三
class=none onmouseover="this.className='over';menuin()"
onmouseout="this.className='none';">菜单项四
class=none onmouseover="this.className='over';menuin()"
onmouseout="this.className='none';">菜单项五
