auto scroll halaman

<script>var xscroll=document.getElementById("un-mutescroll").onclick=function(){playstopscroll()};document.getElementById("un-mutescroll");xscroll=document.getElementById("mutescroll").onclick=function(){playstopscroll()};document.getElementById("mutescroll");var currentpos=0,alt=1,curpos1=0,curpos2=-1,statusscroll=!1;function initialize(){startit()}function scrollwindow(){if(!statusscroll)return!1;document.all?temp=document.body.scrollTop:temp=window.pageYOffset,0==(alt=0==alt?1:0)?curpos1=temp:curpos2=temp,curpos1!=curpos2&&(currentpos=document.all?document.body.scrollTop+1:window.pageYOffset+1,window.scroll(0,currentpos))}function startit(){setInterval("scrollwindow()",10)}function playstopscroll(l=""){(statusscroll=0==l.length?!statusscroll:l)?(document.getElementById("un-mutescroll").style.display="none",document.getElementById("mutescroll").style.display="inline-block"):(document.getElementById("mutescroll").style.display="none",document.getElementById("un-mutescroll").style.display="inline-block")}window.onload=initialize;</script>