$(function () {
$(".sticky").hide();
var top = $(window).scrollTop();
if (top >= 100) {
$(".sticky").show();
}
else {
$(".sticky").hide();
}
$(window).scroll(function () {
var scrollTop = $(this).scrollTop();
if (scrollTop >= 100) {
$(".sticky").show();
}
else {
$(".sticky").hide();
}
});
});
function backTop() {
$('body,html').animate({ scrollTop: 0 }, 1000);
}
javascript onscroll函数
window.onload = function () {
var topbtn = document.getElementById("btn");
var timer = null;
var pagelookheight = document.documentElement.clientHeight;
window.onscroll = function(){
var backtop = document.body.scrollTop;
if(backtop >= pagelookheight){
topbtn.style.display = "block";
}else{
topbtn.style.display = "none";
}
}
topbtn.onclick = function () {
timer = setInterval(function () {
var backtop = document.body.scrollTop;
var speedtop = backtop/5;
document.body.scrollTop = backtop -speedtop;
if(backtop ==0){
clearInterval(timer);
}
}, 30);
}
}