我正在寻找一个简单的,跨浏览器“滚动到顶部”的动画,我可以应用到一个链接。我不想需要一个JS库,如jQuery/Moo等。
// jQuery Equivilant to convert to pure JS...
$('html, body').animate({scrollTop:0}, 400);
对于那些在跳进图书馆之前应该100%学习JS的人来说,我是一个完美的例子。:(
我正在寻找一个简单的,跨浏览器“滚动到顶部”的动画,我可以应用到一个链接。我不想需要一个JS库,如jQuery/Moo等。
// jQuery Equivilant to convert to pure JS...
$('html, body').animate({scrollTop:0}, 400);
对于那些在跳进图书馆之前应该100%学习JS的人来说,我是一个完美的例子。:(
当前回答
我修改了@TimWolla的代码,添加了更多的选项和一些移动功能。 另外,增加了对document.body.scrollTop和document.documentElement.scrollTop的跨浏览器支持
// scroll to top
scrollTo(0, 1000);
// Element to move, time in ms to animate
function scrollTo(element, duration) {
var e = document.documentElement;
if(e.scrollTop===0){
var t = e.scrollTop;
++e.scrollTop;
e = t+1===e.scrollTop--?e:document.body;
}
scrollToC(e, e.scrollTop, element, duration);
}
// Element to move, element or px from, element or px to, time in ms to animate
function scrollToC(element, from, to, duration) {
if (duration <= 0) return;
if(typeof from === "object")from=from.offsetTop;
if(typeof to === "object")to=to.offsetTop;
scrollToX(element, from, to, 0, 1/duration, 20, easeOutCuaic);
}
function scrollToX(element, xFrom, xTo, t01, speed, step, motion) {
if (t01 < 0 || t01 > 1 || speed<= 0) {
element.scrollTop = xTo;
return;
}
element.scrollTop = xFrom - (xFrom - xTo) * motion(t01);
t01 += speed * step;
setTimeout(function() {
scrollToX(element, xFrom, xTo, t01, speed, step, motion);
}, step);
}
function easeOutCuaic(t){
t--;
return t*t*t+1;
}
http://jsfiddle.net/forestrf/tPQSv/
简化版: http://jsfiddle.net/forestrf/tPQSv/139/
// c = element to scroll to or top position in pixels
// e = duration of the scroll in ms, time scrolling
// d = (optative) ease function. Default easeOutCuaic
function scrollTo(c,e,d){d||(d=easeOutCuaic);var a=document.documentElement;if(0===a.scrollTop){var b=a.scrollTop;++a.scrollTop;a=b+1===a.scrollTop--?a:document.body}b=a.scrollTop;0>=e||("object"===typeof b&&(b=b.offsetTop),"object"===typeof c&&(c=c.offsetTop),function(a,b,c,f,d,e,h){function g(){0>f||1<f||0>=d?a.scrollTop=c:(a.scrollTop=b-(b-c)*h(f),f+=d*e,setTimeout(g,e))}g()}(a,b,c,0,1/e,20,d))};
function easeOutCuaic(t){
t--;
return t*t*t+1;
}
其他回答
我看到上面大多数/所有的帖子都是用javascript搜索按钮的。这是有效的,只要你只有一个按钮。我建议在按钮内定义一个“onclick”元素。然后,“onclick”将调用该函数,使其滚动。
如果你这样做,你可以使用多个按钮,只要按钮看起来像这样:
<button onclick="scrollTo(document.body, 0, 1250)">To the top</button>
改编自下面的回答:
function scroll(y, duration) {
var initialY = document.documentElement.scrollTop || document.body.scrollTop;
var baseY = (initialY + y) * 0.5;
var difference = initialY - baseY;
var startTime = performance.now();
function step() {
var normalizedTime = (performance.now() - startTime) / duration;
if (normalizedTime > 1) normalizedTime = 1;
window.scrollTo(0, baseY + difference * Math.cos(normalizedTime * Math.PI));
if (normalizedTime < 1) window.requestAnimationFrame(step);
}
window.requestAnimationFrame(step);
}
这应该允许你平滑地滚动(余弦函数)从任何地方到指定的“y”。
使用这个解决方案
animate(document.documentElement, 'scrollTop', 0, 200);
谢谢
这是一种基于上述答案的跨浏览器方法
function scrollTo(to, duration) {
if (duration < 0) return;
var scrollTop = document.body.scrollTop + document.documentElement.scrollTop;
var difference = to - scrollTop;
var perTick = difference / duration * 10;
setTimeout(function() {
scrollTop = scrollTop + perTick;
document.body.scrollTop = scrollTop;
document.documentElement.scrollTop = scrollTop;
if (scrollTop === to) return;
scrollTo(to, duration - 10);
}, 10);
}
看来已经有很多解决方案了。不管怎样,这是另一个,使用简化方程。
// first add raf shim
// http://www.paulirish.com/2011/requestanimationframe-for-smart-animating/
window.requestAnimFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
function( callback ){
window.setTimeout(callback, 1000 / 60);
};
})();
// main function
function scrollToY(scrollTargetY, speed, easing) {
// scrollTargetY: the target scrollY property of the window
// speed: time in pixels per second
// easing: easing equation to use
var scrollY = window.scrollY || document.documentElement.scrollTop,
scrollTargetY = scrollTargetY || 0,
speed = speed || 2000,
easing = easing || 'easeOutSine',
currentTime = 0;
// min time .1, max time .8 seconds
var time = Math.max(.1, Math.min(Math.abs(scrollY - scrollTargetY) / speed, .8));
// easing equations from https://github.com/danro/easing-js/blob/master/easing.js
var easingEquations = {
easeOutSine: function (pos) {
return Math.sin(pos * (Math.PI / 2));
},
easeInOutSine: function (pos) {
return (-0.5 * (Math.cos(Math.PI * pos) - 1));
},
easeInOutQuint: function (pos) {
if ((pos /= 0.5) < 1) {
return 0.5 * Math.pow(pos, 5);
}
return 0.5 * (Math.pow((pos - 2), 5) + 2);
}
};
// add animation loop
function tick() {
currentTime += 1 / 60;
var p = currentTime / time;
var t = easingEquations[easing](p);
if (p < 1) {
requestAnimFrame(tick);
window.scrollTo(0, scrollY + ((scrollTargetY - scrollY) * t));
} else {
console.log('scroll done');
window.scrollTo(0, scrollTargetY);
}
}
// call it once to get started
tick();
}
// scroll it!
scrollToY(0, 1500, 'easeInOutQuint');