双击网页向上滚动

var currentpos,timer; function initialize() {     timer=setInterval("scrollwindow()",10);} function sc(){    clearInterval(timer); }function scrollwindow(){ currentpos=document.body.scrollTop; window.scroll(0,++currentpos); if (currentpos != document.body.scrollTop) sc();} document.onmousedown=sc;document.ondblclick=initialize;