要在精确的时间内滚动到某个位置,window.requestAnimationFrame
可以使用,每次计算适当的当前位置。不支持setTimeout
时可用于类似效果requestAnimationFrame
。
/*
@param pos: the y-position to scroll to (in pixels)
@param time: the exact amount of time the scrolling will take (in milliseconds)
*/
function scrollToSmoothly(pos, time) {
var currentPos = window.pageYOffset;
var start = null;
if(time == null) time = 500;
pos = +pos, time = +time;
window.requestAnimationFrame(function step(currentTime) {
start = !start ? currentTime : start;
var progress = currentTime - start;
if (currentPos < pos) {
window.scrollTo(0, ((pos - currentPos) * progress / time) + currentPos);
} else {
window.scrollTo(0, currentPos - ((currentPos - pos) * progress / time));
}
if (progress < time) {
window.requestAnimationFrame(step);
} else {
window.scrollTo(0, pos);
}
});
}
演示:
/*
@param time: the exact amount of time the scrolling will take (in milliseconds)
@param pos: the y-position to scroll to (in pixels)
*/
function scrollToSmoothly(pos, time) {
var currentPos = window.pageYOffset;
var start = null;
if(time == null) time = 500;
pos = +pos, time = +time;
window.requestAnimationFrame(function step(currentTime) {
start = !start ? currentTime : start;
var progress = currentTime - start;
if (currentPos < pos) {
window.scrollTo(0, ((pos - currentPos) * progress / time) + currentPos);
} else {
window.scrollTo(0, currentPos - ((currentPos - pos) * progress / time));
}
if (progress < time) {
window.requestAnimationFrame(step);
} else {
window.scrollTo(0, pos);
}
});
}
<button onClick="scrollToSmoothly(document.querySelector('div').offsetTop, 300)">
Scroll To Div (300ms)
</button>
<button onClick="scrollToSmoothly(document.querySelector('div').offsetTop, 200)">
Scroll To Div (200ms)
</button>
<button onClick="scrollToSmoothly(document.querySelector('div').offsetTop, 100)">
Scroll To Div (100ms)
</button>
<button onClick="scrollToSmoothly(document.querySelector('div').offsetTop, 50)">
Scroll To Div (50ms)
</button>
<button onClick="scrollToSmoothly(document.querySelector('div').offsetTop, 1000)">
Scroll To Div (1000ms)
</button>
<div style="margin: 500px 0px;">
DIV<p/>
<button onClick="scrollToSmoothly(0, 500)">
Back To Top
</button>
<button onClick="scrollToSmoothly(document.body.scrollHeight)">
Scroll To Bottom
</button>
</div>
<div style="margin: 500px 0px;">
</div>
<button style="margin-top: 100px;" onClick="scrollToSmoothly(500, 3000)">
Scroll To y-position 500px (3000ms)
</button>
对于更复杂的情况,可以使用SmoothScroll.js 库,它处理垂直和水平平滑滚动、在其他容器元素内部滚动、不同的缓动行为、从当前位置相对滚动等等。
var easings = document.getElementById("easings");
for(var key in smoothScroll.easing){
if(smoothScroll.easing.hasOwnProperty(key)){
var option = document.createElement('option');
option.text = option.value = key;
easings.add(option);
}
}
document.getElementById('to-bottom').addEventListener('click', function(e){
smoothScroll({yPos: 'end', easing: easings.value, duration: 2000});
});
document.getElementById('to-top').addEventListener('click', function(e){
smoothScroll({yPos: 'start', easing: easings.value, duration: 2000});
});
<script src="https://cdn.jsdelivr.net/gh/LieutenantPeacock/SmoothScroll@1.2.0/src/smoothscroll.min.js" integrity="sha384-UdJHYJK9eDBy7vML0TvJGlCpvrJhCuOPGTc7tHbA+jHEgCgjWpPbmMvmd/2bzdXU" crossorigin="anonymous"></script>
<!-- Taken from one of the library examples -->
Easing: <select id="easings"></select>
<button id="to-bottom">Scroll To Bottom</button>
<br>
<button id="to-top" style="margin-top: 5000px;">Scroll To Top</button>
或者,您可以传递一个选项对象,window.scroll
该对象滚动到特定的 x 和 y 位置,并window.scrollBy
从当前位置滚动一定量:
// Scroll to specific values
// scrollTo is the same
window.scroll({
top: 2500,
left: 0,
behavior: 'smooth'
});
// Scroll certain amounts from current position
window.scrollBy({
top: 100, // could be negative value
left: 0,
behavior: 'smooth'
});
演示:
<button onClick="scrollToDiv()">Scroll To Element</button>
<div style="margin: 500px 0px;">Div</div>
<script>
function scrollToDiv(){
var elem = document.querySelector("div");
window.scroll({
top: elem.offsetTop,
left: 0,
behavior: 'smooth'
});
}
</script>
如果您只需要滚动到一个元素,而不是文档中的特定位置,则可以使用Element.scrollIntoView
with behavior
set to smooth
。
document.getElementById("elemID").scrollIntoView({
behavior: 'smooth'
});
演示:
<button onClick="scrollToDiv()">Scroll To Element</button>
<div id="myDiv" style="margin: 500px 0px;">Div</div>
<script>
function scrollToDiv(){
document.getElementById("myDiv").scrollIntoView({
behavior: 'smooth'
});
}
</script>
现代浏览器支持scroll-behavior
CSS 属性,可用于使文档滚动顺畅(无需 JavaScript)。锚标记可以通过给锚标签可以用于此href
的#
加id
的元素滚动到)。您还可以为scroll-behavior
特定容器设置属性,例如 adiv
以使其内容平滑滚动。
演示:
html, body{
scroll-behavior: smooth;
}
a, a:visited{
color: initial;
}
<a href="#elem">Scroll To Element</a>
<div id="elem" style="margin: 500px 0px;">Div</div>
scroll-behavior
当使用 .css 时,CSS属性也适用于 JavaScript window.scrollTo
。
演示:
html, body{
scroll-behavior: smooth;
}
<button onClick="scrollToDiv()">Scroll To Element</button>
<div style="margin: 500px 0px;">Div</div>
<script>
function scrollToDiv(){
var elem = document.querySelector("div");
window.scrollTo(0, elem.offsetTop);
}
</script>
要检查该scroll-behavior
属性是否受支持,您可以检查它是否作为 HTML 元素样式中的键存在。
var scrollBehaviorSupported = 'scroll-behavior' in document.documentElement.style;
console.log('scroll-behavior supported:', scrollBehaviorSupported);