会写greasemonkey脚本的指教一下

<div id="MFX2" style="overflow: auto;position:absolute; width:206px; height:24px; z-index:2; left:10px; top: 110px; visibility: hidden"><a href="upla/nsub_pyjh.html" target="topMenu" onclick="parent.mainFrame.location.href='sub_blank.html'" style="color:#242424;font-size:17px;">计划</a></div>
如何利用脚本 把 visibility：hidden改成 visiable
——我喂自己袋盐
>>Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Iron/31.0.1700.0 Chrome/31.0.1700.0 Safari/537.36