// 原生JS window.onload = function () { document.getElementById("btn").onclick = function () { timer = setInterval(function () { var scrollTop = window.pageYOffset || document.documentElement.scrollTop || document.body.scrollTop || 0; var speed = -100; if (scrollTop == 0) { clearInterval(timer); } // 相容寫法: // document.documentElement.scrollTop = document.body.scrollTop = window.pageYOffset = scrollTop + speed; document.body.scrollTop = scrollTop + speed; }, 30) } } // JQ 寫法 $(function () { $("#btn").click(function(){ $('body,html').animate({scrollTop:0},1000); return false; }); });