代码如下，好像没啥好说的，自己看吧

var currentpos,timer;//js页面双击滚动
function initialize() { 
	timer=setInterval("scrollwindow()",20); //滚动间隔20ms
} 
function sc(){ 
	clearInterval(timer);
} 
function scrollwindow() { 
	currentpos=document.body.scrollTop; 
	window.scroll(0,++currentpos); 
	if (currentpos != document.body.scrollTop) 
	sc(); 
}
document.onmousedown=sc;//单击左键
document.ondblclick=initialize;//双击左键