最近在复习前端的知识，无聊写了个返回顶部按钮。已兼容所有浏览器。
PS：不要在意我用的是H5的规范写的页面，JS代码才是核心
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title></title>
<style>
body {
height: 2000px;
}
#topbtn {
position: absolute;
right: 5%;
}
</style>
</head>
<body>
<script type="text/javascript">
window.onload = function() {
var t = document.createElement('div');
t.setAttribute('id','topbtn');
t.innerText = 'Top';
t.style.top = document.documentElement.clientHeight - 80 + 'px';
t.style.cursor = 'pointer';
document.body.appendChild(t);
if(window.attachEvent) {
t.attachEvent('onclick',function() {
window.scrollTo(0,0);
});
window.attachEvent('onscroll',function() {
var scrollTop = document.documentElement.scrollTop || window.pageYOffset || document.body.scrollTop;
t.style.top = scrollTop + document.documentElement.clientHeight -80 + 'px';
});
}
else {
t.addEventListener('click',function() {
window.scrollTo(0,0);
});
window.addEventListener('scroll',function() {
var scrollTop = document.documentElement.scrollTop || window.pageYOffset || document.body.scrollTop;
t.style.top = scrollTop + document.documentElement.clientHeight -80 + 'px';
});
}
}
</script>
</body>
</html>