<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
aside {
position: absolute;
left: 50%;
top: 300px;
margin-left: 600px;
width: 45px;
height: 130px;
background: aqua;
}
.w {
width: 1200px;
margin: 10px auto;
}
header {
height: 150px;
background-color: palegreen;
}
.banner {
height: 250px;
background-color: plum;
}
main {
height: 1000px;
background-color: purple;
}
span {
display: none;
position: absolute;
bottom: 0;
}
</style>
<script>
window.onload = function () {
let aside = document.querySelector('aside')
let banner = document.querySelector('.banner')
let bannerOffsetTop = banner.offsetTop
let offset = aside.offsetTop - bannerOffsetTop
let main = document.querySelector('main')
let goBack = document.querySelector('.go-back')
document.addEventListener('scroll', function () {
// console.log('banner.offsetTop:', banner.offsetTop)
console.log('window.pageYOffset', window.pageYOffset)
if(window.pageYOffset > banner.offsetTop) {
aside.style.position = 'fixed'
aside.style.top = offset + 'px'
console.log(1111111111)
} else {
aside.style.position = 'absolute'
aside.style.top = '300px'
console.log(222222222222222)
}
if(window.pageYOffset > main.offsetTop) {
goBack.style.display = 'block'
} else {
goBack.style.display = 'none'
}
})
goBack.addEventListener('click', function () {
// window.scroll({
// top:0,left:0,behavior:'smooth'
// })
animate(window, 0)
})
}
function animate(obj, target, callback) {
clearInterval(obj.timer)
obj.timer = setInterval(function () {
if(target === window.pageYOffset) {
clearInterval(obj.timer)
callback && callback
}
let step = (target - window.pageYOffset) / 10
step = step > 0 ? Math.ceil(step) : Math.floor(step)
// window.scroll({
// top: 0, left: 0, behavior: 'smooth'
// })
window.scroll(0, window.pageYOffset + step)
}, 10)
}
</script>
</head>
<body>
<aside>
<span class="go-back">go-back</span>
</aside>
<header class="w">header</header>
<div class="banner w">banner</div>
<main class="w">main</main>
</body>
</html>
<!DOCTYPE html>
<html lang="en-US">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<script>
let btn, timer, scrollTop
window.onload = () => {
console.log(article)
btn = document.querySelector('button')
btn.onclick = function() {
console.log('btn')
timer = setInterval(function() {
document.documentElement.scrollTop -= 30
}, 200)
}
}
window.onscroll = function() {
if(document.documentElement.scrollTop >= scrollTop) {
clearInterval(timer)
}
scrollTop = document.documentElement.scrollTop
console.log('%' * 30, scrollTop)
}
</script>
<body>
<style>
body {
width: 2000px;
height: 2000px;
}
* {
margin: 0;
padding: 0;
}
article {
width: 300px;
height: 1100px;
background-color: purple;
}
button {
width: 50px;
height: 50px;
background-color: peru;
position: fixed;
bottom: 50px;
right: 50px;
}
</style>
<article id="article"></article>
<button id="btn">btn</button>
<script>
// console.log(window.alert('alert'));
// console.log(window.confirm('confirm'));
// console.log(window.prompt('prompt'));
function showLocation() {
let log = [
'Property (typeof): Value',
`location (${typeof location}): ${location}`,
]
for(const prop in location) {
log.push(
`${prop} (${typeof location[prop]}): ${location[prop] || 'n/a'}`
)
}
console.log(log.join('\n'))
}
window.onresize = function() {
console.log(this, 'onresize')
}
</script>
</body>
</html>
