使用 Javascript 滚动网页,其滚动在页面中间触发
Scroll a web page using Javascript whose scroll triggers at the middle of page
我遇到过一些底部有页脚的网站,当我滚动到页脚上方的区域时,滚动实际上发生了。
要自动滚动这些页面,但我的代码目前的问题是它位于页面底部,我直接到达页脚,因此不会触发位于页脚上方的滚动触发器。
有什么方法可以达到同样的目的吗?
这是我目前从控制台执行的尝试:
(function() {
var intervalObj = null;
var retry = 0;
var clickHandler = function() {
console.log("Clicked; stopping autoscroll");
clearInterval(intervalObj);
document.body.removeEventListener("click", clickHandler);
}
function scrollDown() {
var scrollHeight = document.body.scrollHeight,
scrollTop = document.body.scrollTop,
innerHeight = window.innerHeight,
difference = (scrollHeight - scrollTop) - innerHeight
if (difference > 0) {
window.scrollBy(0, difference);
if (retry > 0) {
retry = 0;
}
console.log("scrolling down more");
} else {
if (retry >= 3) {
console.log("reached bottom of page; stopping");
clearInterval(intervalObj);
document.body.removeEventListener("click", clickHandler);
} else {
console.log("[apparenty] hit bottom of page; retrying: " + (retry + 1));
retry++;
}
}
}
document.body.addEventListener("click", clickHandler);
intervalObj = setInterval(scrollDown, 1000);
})()
有很多网站有这个功能,要测试同一个网站你可以试试
https://www.zomato.com/bangalore/indiranagar-restaurants
注意:与此类似的问题没有回答如何在页面的某个中间点滚动,而是直接将我带到页脚,所以这不是重复的
逻辑是保留到Scroller中间,除非页面完全加载。我们可以稍微调整代码以获得滚动条的最后位置。试试这个:
var scrollHeight = 0,
newScrollHeight;
do {
window.scrollTo(0, document.body.scrollHeight / 2);
newScrollHeight = document.body.scrollHeight / 2;
if (newScrollHeight == scrollHeight) {
break;
} else {
scrollHeight = newScrollHeight;
}
} while (true);
虽然Kumar Rishabh已经回答了你的问题,但对于这种情况,我还有另一种解决方案。
设置域以检测用户是否滚动到域。
效果就像您提供的网站一样。 https://www.zomato.com/bangalore/indiranagar-restaurants
我用纯Javascript为你做了一些简单的例子。
片段核心代码:
// Here is domain to detect if user scroll into.
if (
triggerDomain.getBoundingClientRect().top < window.innerHeight &&
triggerDomain.getBoundingClientRect().bottom > 0
) {
if (getMore === false) {
getMore = true
// Do something you want here ....
console.info('got more !!')
完整代码示例,检查代码片段:
const rootElement = document.getElementById("rootDiv");
const triggerDomain = document.getElementById("triggerDomain");
let getMore = false;
function detectScrollIntoDomain() {
// Here is domain to detect if user scroll into.
if (
triggerDomain.getBoundingClientRect().top < window.innerHeight &&
triggerDomain.getBoundingClientRect().bottom > 0
) {
if (getMore === false) {
getMore = true;
// Do something you want here ....
console.info("got more !!");
setTimeout(() => {
let currentScrollTop = rootElement.scrollTop;
for (let i = 0; i < 15; i++) {
let r = Math.floor(Math.random() * 255);
let g = Math.floor(Math.random() * 255);
let b = Math.floor(Math.random() * 255);
const contentElement = document.getElementById("content");
const card = document.createElement("div");
card.className = "contentCard";
card.style.backgroundColor = `rgba(${r}, ${g}, ${b})`;
contentElement.appendChild(card);
}
rootElement.scrollTo(0, currentScrollTop);
// Don't forget to set flag to `false`.
getMore = false;
}, 200);
}
}
}
rootElement.addEventListener("scroll", detectScrollIntoDomain, {
passive: true
});
html,
body {
position: relative;
font-family: sans-serif;
padding: 0;
margin: 0;
height: 100%;
width: 100%;
}
h1,
h2 {
margin: 0;
color: aliceblue;
}
#rootDiv {
position: relative;
overflow: auto;
height: 100%;
width: 100%;
}
#header {
height: 200px;
background-color: rgb(112, 112, 112);
}
#content {
display: flex;
flex-wrap: wrap;
position: relative;
height: fit-content;
background-color: rgb(136, 136, 136);
}
#content div:first-child {
height: 600px;
width: 100%;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
#triggerDomain {
position: absolute;
bottom: 0px;
outline: 1px dashed rgb(3, 25, 119);
height: 500px;
width: 100%;
background: repeating-linear-gradient(
135deg,
rgba(46, 45, 45, 0.3) 0,
rgba(46, 45, 45, 0.3) 10px,
rgba(136, 136, 136, 0.3) 10px,
rgba(136, 136, 136, 0.3) 20px
);
}
#footer {
height: 180%;
background-color: rgb(112, 112, 112);
}
.contentCard {
width: 180px;
height: 180px;
margin: 12px;
border-radius: 8px;
background-color: aquamarine;
}
<!DOCTYPE html>
<html>
<head>
<title>Parcel Sandbox</title>
<meta charset="UTF-8" />
<link rel="stylesheet" type="text/css" href="./src/styles.css"
</head>
<body>
<div id="rootDiv">
<div id="header">
<h1>Header</h1>
</div>
<div id="content">
<div>
<h2>Content</h2>
<h2>Scroll down to get more cards.</h2>
</div>
<div id="triggerDomain">
<h2>Trigger domain</h2>
</div>
</div>
<div id="footer">
<h2>Footer</h2>
</div>
</div>
<script src="src/index.js"></script>
</body>
</html>
希望能帮到你!
我遇到过一些底部有页脚的网站,当我滚动到页脚上方的区域时,滚动实际上发生了。
要自动滚动这些页面,但我的代码目前的问题是它位于页面底部,我直接到达页脚,因此不会触发位于页脚上方的滚动触发器。
有什么方法可以达到同样的目的吗?
这是我目前从控制台执行的尝试:
(function() {
var intervalObj = null;
var retry = 0;
var clickHandler = function() {
console.log("Clicked; stopping autoscroll");
clearInterval(intervalObj);
document.body.removeEventListener("click", clickHandler);
}
function scrollDown() {
var scrollHeight = document.body.scrollHeight,
scrollTop = document.body.scrollTop,
innerHeight = window.innerHeight,
difference = (scrollHeight - scrollTop) - innerHeight
if (difference > 0) {
window.scrollBy(0, difference);
if (retry > 0) {
retry = 0;
}
console.log("scrolling down more");
} else {
if (retry >= 3) {
console.log("reached bottom of page; stopping");
clearInterval(intervalObj);
document.body.removeEventListener("click", clickHandler);
} else {
console.log("[apparenty] hit bottom of page; retrying: " + (retry + 1));
retry++;
}
}
}
document.body.addEventListener("click", clickHandler);
intervalObj = setInterval(scrollDown, 1000);
})()
有很多网站有这个功能,要测试同一个网站你可以试试
https://www.zomato.com/bangalore/indiranagar-restaurants
注意:与此类似的问题没有回答如何在页面的某个中间点滚动,而是直接将我带到页脚,所以这不是重复的
逻辑是保留到Scroller中间,除非页面完全加载。我们可以稍微调整代码以获得滚动条的最后位置。试试这个:
var scrollHeight = 0,
newScrollHeight;
do {
window.scrollTo(0, document.body.scrollHeight / 2);
newScrollHeight = document.body.scrollHeight / 2;
if (newScrollHeight == scrollHeight) {
break;
} else {
scrollHeight = newScrollHeight;
}
} while (true);
虽然Kumar Rishabh已经回答了你的问题,但对于这种情况,我还有另一种解决方案。
设置域以检测用户是否滚动到域。 效果就像您提供的网站一样。 https://www.zomato.com/bangalore/indiranagar-restaurants
我用纯Javascript为你做了一些简单的例子。
片段核心代码:
// Here is domain to detect if user scroll into.
if (
triggerDomain.getBoundingClientRect().top < window.innerHeight &&
triggerDomain.getBoundingClientRect().bottom > 0
) {
if (getMore === false) {
getMore = true
// Do something you want here ....
console.info('got more !!')
完整代码示例,检查代码片段:
const rootElement = document.getElementById("rootDiv");
const triggerDomain = document.getElementById("triggerDomain");
let getMore = false;
function detectScrollIntoDomain() {
// Here is domain to detect if user scroll into.
if (
triggerDomain.getBoundingClientRect().top < window.innerHeight &&
triggerDomain.getBoundingClientRect().bottom > 0
) {
if (getMore === false) {
getMore = true;
// Do something you want here ....
console.info("got more !!");
setTimeout(() => {
let currentScrollTop = rootElement.scrollTop;
for (let i = 0; i < 15; i++) {
let r = Math.floor(Math.random() * 255);
let g = Math.floor(Math.random() * 255);
let b = Math.floor(Math.random() * 255);
const contentElement = document.getElementById("content");
const card = document.createElement("div");
card.className = "contentCard";
card.style.backgroundColor = `rgba(${r}, ${g}, ${b})`;
contentElement.appendChild(card);
}
rootElement.scrollTo(0, currentScrollTop);
// Don't forget to set flag to `false`.
getMore = false;
}, 200);
}
}
}
rootElement.addEventListener("scroll", detectScrollIntoDomain, {
passive: true
});
html,
body {
position: relative;
font-family: sans-serif;
padding: 0;
margin: 0;
height: 100%;
width: 100%;
}
h1,
h2 {
margin: 0;
color: aliceblue;
}
#rootDiv {
position: relative;
overflow: auto;
height: 100%;
width: 100%;
}
#header {
height: 200px;
background-color: rgb(112, 112, 112);
}
#content {
display: flex;
flex-wrap: wrap;
position: relative;
height: fit-content;
background-color: rgb(136, 136, 136);
}
#content div:first-child {
height: 600px;
width: 100%;
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
}
#triggerDomain {
position: absolute;
bottom: 0px;
outline: 1px dashed rgb(3, 25, 119);
height: 500px;
width: 100%;
background: repeating-linear-gradient(
135deg,
rgba(46, 45, 45, 0.3) 0,
rgba(46, 45, 45, 0.3) 10px,
rgba(136, 136, 136, 0.3) 10px,
rgba(136, 136, 136, 0.3) 20px
);
}
#footer {
height: 180%;
background-color: rgb(112, 112, 112);
}
.contentCard {
width: 180px;
height: 180px;
margin: 12px;
border-radius: 8px;
background-color: aquamarine;
}
<!DOCTYPE html>
<html>
<head>
<title>Parcel Sandbox</title>
<meta charset="UTF-8" />
<link rel="stylesheet" type="text/css" href="./src/styles.css"
</head>
<body>
<div id="rootDiv">
<div id="header">
<h1>Header</h1>
</div>
<div id="content">
<div>
<h2>Content</h2>
<h2>Scroll down to get more cards.</h2>
</div>
<div id="triggerDomain">
<h2>Trigger domain</h2>
</div>
</div>
<div id="footer">
<h2>Footer</h2>
</div>
</div>
<script src="src/index.js"></script>
</body>
</html>
希望能帮到你!