js控制的回到頁面頂端goTop的程式碼實作_javascript技巧

複製程式碼


程式碼如下


function goTop(){
var _btn = document.getElementById("goTop");
if (document.documentElement && document.documentElement. document.documentElement;
} else if (document.body) {
var _con = document.body;
}
window.onscroll = set;
_btn.style.🎜>window.onscroll = set;
_btn.style.left = document.onscroll = document. documentElement.scrollWidth/2 500 "px";
_btn.onclick = function (){
_btn.style.display = "none";
window.onscroll = null;
this.timer = setInterval(function() {
_con.scrollTop -= Math.ceil(_con.scrollTop * 0.3);
if (_con.scrollTop == 0) clearInterval(_btn.timer, window.onscroll = set);
},10);