界面滚动到相应的位置

function scroll(obj/*要滚动到的位置的元素*/){ 

var scrollHeight = obj.offsetTop;
clearInterval(obj.timer);
obj.timer = setInterval(function(){

var bodyScroll = document.documentElement.scrollTop || document.body.scrollTop;

if(bodyScroll == scrollHeight ) clearInterval(obj.timer);

var iSpeed = (scrollHeight - bodyScroll) / 5;

iSpeed = iSpeed > 0 ? Math.ceil(iSpeed) : Math.floor(iSpeed);

bodyScroll += iSpeed;

document.body.scrollTop = bodyScroll;

document.documentElement.scrollTop = bodyScroll;

},50);

}