查看“MediaWiki:Common.js”的源代码

/* 这里的任何JavaScript将为所有用户在每次页面载入时加载。 */
<script type="text/javascript">
function goTopEx(){
        var obj=document.getElementById("goTopBtn");
        function getScrollTop(){
                return document.documentElement.scrollTop;
            }
        function setScrollTop(value){
                document.documentElement.scrollTop=value;
            }    
        window.onscroll=function(){getScrollTop()>0?obj.style.display="":obj.style.display="none";}
        obj.onclick=function(){
            var goTop=setInterval(scrollMove,10);
            function scrollMove(){
                    setScrollTop(getScrollTop()/1.1);
                    if(getScrollTop()<1)clearInterval(goTop);
                }
        }
    }
</script>
<style>
#goTopBtn {
	POSITION: fixed; TEXT-ALIGN: center; LINE-HEIGHT: 30px; WIDTH: 30px; BOTTOM: 35px; HEIGHT: 33px; FONT-SIZE: 12px; CURSOR: pointer; RIGHT: 0px; _position: absolute; _right: auto
}
</style>
<DIV style="DISPLAY: none" id=goTopBtn><IMG border=0 src="http://www.zzbaike.com/w/skins/vector/images/lanren_top.jpg"></DIV>
<SCRIPT type="text/javascript">goTopEx();</SCRIPT>