//------------------------------------点击按钮------------------------------------
<span onClick="gotoTop(‘2‘,‘2‘);return false;"></span>
//------------------------------------js------------------------------------
<script type="text/javascript">
function gotoTop(acceleration,stime) {
??acceleration = acceleration || 0.1;
??stime = stime || 10;
??var x1 = 0;
??var y1 = 0;
??var x2 = 0;
??var y2 = 0;
??var x3 = 0;
??var y3 = 0;
??if (document.documentElement) {
??????x1 = document.documentElement.scrollLeft || 0;
??????y1 = document.documentElement.scrollTop || 0;
??}
??if (document.body) {
??????x2 = document.body.scrollLeft || 0;
??????y2 = document.body.scrollTop || 0;
??}
??var x3 = window.scrollX || 0;
??var y3 = window.scrollY || 0;
??var x = Math.max(x1, Math.max(x2, x3));
??var y = Math.max(y1, Math.max(y2, y3));
??var speeding = 1 + acceleration;
??window.scrollTo(Math.floor(x / speeding), Math.floor(y / speeding));
??if(x > 0 || y > 0) {
??????var run = "gotoTop(" + acceleration + ", " + stime + ")";
??????window.setTimeout(run, stime);
??};
}
</script>
js实现点击定位最顶端
原文地址：http://www.cnblogs.com/kongxc/p/7469041.html