原生js ~~~ // 返回顶部 if ( $("#returnTop").length ) { var _obj = document.getElementById("contents"); var btn = document.getElementById("returnTop"); var now = _obj.scrollTop; btn.onclick = function() { var timer = setInterval(function() { now = _obj.scrollTop; //滚动条竖直距离 speed = (0 - now) / 10; speed = Math.floor(speed); if (now == 0) { clearInterval(timer); } else { _objscrollTop = now + speed; //标准模式下的浏览器 _obj.scrollTop = now + speed; //怪异模式下的浏览器 } }, 10); } } ~~~ jquery ~~~ // totop $('[scroll="top"]').on("click",function(){ $("body,html").animate({scrollTop:0}); }); ~~~