js实现可关闭的悬浮层的代码

<div id="welcome" style="border: 2px solid rgb(0, 17, 34); padding: 30px 10px 10px; background: rgb(18, 51, 85) none repeat scroll 0% 0%; position: absolute; width: 160px; right: 8px; bottom: 4px; visibility: visible; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; z-index: 99; color: rgb(255, 255, 255); text-align: left;">

 <div id="welcome_close" style="position: absolute; top: 5px; right: 5px;">
       <a href="javascript:;" style="color: rgb(255, 165, 0);" onclick="document.getElementById('welcome').style.visibility = 'hidden';">
     <span>关闭</span>
 </a>
 </div>
 脚本学堂，可关闭的悬浮层效果。运行下看效果。
 </div>