仅当在特定div的视图上滚动时才激活CSS动画 [英] Active CSS animation only when you scroll on the view of the specific div
本文介绍了仅当在特定div的视图上滚动时才激活CSS动画的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个用CSS和HTML制作的图表,该图表中有一个动画来加载图表.我只想在包含图表的div视图上滚动时才开始播放此动画.
我只想在页面上查看图表时才收费,我知道我必须使用JavaScript,但是我是JS的初学者,所以我不知道是否有可能做点什么这样.
这是图表的小提琴:
https://jsfiddle.net/matteous1/pdL0kbqk/
HTML
<ul class="chart">
<li>
<span style="height:5%; background: rgba(0, 102, 255, 0.80);" title="ActionScript"></span>
</li>
<li>
<span style="height:70%; background: rgba(204, 51, 51, 0.80);" title="JavaScript"></span>
</li>
<li>
<span style="height:50%; background: rgba(255, 186, 2, 0.80);" title="CoffeScript"></span>
</li>
<li>
<span style="height:75%; background: rgba(0, 153, 102, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:90%; background: rgba(0, 102, 255, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:15%; background: rgba(204, 51, 51, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:40%; background: rgba(255, 186, 2, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:55%; background: rgba(0, 153, 102, 0.80);" title="HTML"></span>
</li>
</ul>
CSS
.chart {
display: table;
table-layout: fixed;
width: 90%;
/*max-width: 700px;*/
height: 65%;
margin: 0 auto;
background-image: linear-gradient(to top, rgba(0, 0, 0, 0.1) 2%, rgba(0, 0, 0, 0) 2%);
background-size: 100% 50px;
background-position: left top;
}
.chart li {
position: relative;
display: table-cell;
vertical-align: bottom;
height: 200px;
}
.chart span {
margin: 0 1em;
display: block;
/*background: rgba(209, 236, 250, 0.75);*/
animation: draw 1s ease-in-out;
}
.chart span:before {
position: absolute;
left: 0;
right: 0;
top: 100%;
padding: 5px 1em 0;
display: block;
text-align: center;
content: attr(title);
word-wrap: break-word;
}
@keyframes draw {
0% {
height: 0;
}
}
解决方案
您可以使用onscroll事件并检查元素是否在视口中
document.addEventListener('DOMContentLoaded', function() {
var charElem = document.querySelector('.chart');
var isVisible = false;
window.onscroll = function() {
if(isElementInViewport(charElem) && !isVisible) {
charElem.className += " anim";
isVisible = true;
}
}
function isElementInViewport (el) {
//special bonus for those using jQuery
if (typeof jQuery === "function" && el instanceof jQuery) {
el = el[0];
}
var rect = el.getBoundingClientRect();
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && /*or $(window).height() */
rect.right <= (window.innerWidth || document.documentElement.clientWidth) /*or $(window).width() */
);
}
});
https://jsfiddle.net/karthick6891/pdL0kbqk/1/ >
注意:视口代码中的元素是此链接的引用https://jsfiddle.net/matteous1/pdL0kbqk/
HTML
<ul class="chart">
<li>
<span style="height:5%; background: rgba(0, 102, 255, 0.80);" title="ActionScript"></span>
</li>
<li>
<span style="height:70%; background: rgba(204, 51, 51, 0.80);" title="JavaScript"></span>
</li>
<li>
<span style="height:50%; background: rgba(255, 186, 2, 0.80);" title="CoffeScript"></span>
</li>
<li>
<span style="height:75%; background: rgba(0, 153, 102, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:90%; background: rgba(0, 102, 255, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:15%; background: rgba(204, 51, 51, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:40%; background: rgba(255, 186, 2, 0.80);" title="HTML"></span>
</li>
<li>
<span style="height:55%; background: rgba(0, 153, 102, 0.80);" title="HTML"></span>
</li>
</ul>
CSS
.chart {
display: table;
table-layout: fixed;
width: 90%;
/*max-width: 700px;*/
height: 65%;
margin: 0 auto;
background-image: linear-gradient(to top, rgba(0, 0, 0, 0.1) 2%, rgba(0, 0, 0, 0) 2%);
background-size: 100% 50px;
background-position: left top;
}
.chart li {
position: relative;
display: table-cell;
vertical-align: bottom;
height: 200px;
}
.chart span {
margin: 0 1em;
display: block;
/*background: rgba(209, 236, 250, 0.75);*/
animation: draw 1s ease-in-out;
}
.chart span:before {
position: absolute;
left: 0;
right: 0;
top: 100%;
padding: 5px 1em 0;
display: block;
text-align: center;
content: attr(title);
word-wrap: break-word;
}
@keyframes draw {
0% {
height: 0;
}
}
解决方案
You can use onscroll event and check if the element is in viewport
document.addEventListener('DOMContentLoaded', function() {
var charElem = document.querySelector('.chart');
var isVisible = false;
window.onscroll = function() {
if(isElementInViewport(charElem) && !isVisible) {
charElem.className += " anim";
isVisible = true;
}
}
function isElementInViewport (el) {
//special bonus for those using jQuery
if (typeof jQuery === "function" && el instanceof jQuery) {
el = el[0];
}
var rect = el.getBoundingClientRect();
return (
rect.top >= 0 &&
rect.left >= 0 &&
rect.bottom <= (window.innerHeight || document.documentElement.clientHeight) && /*or $(window).height() */
rect.right <= (window.innerWidth || document.documentElement.clientWidth) /*or $(window).width() */
);
}
});
https://jsfiddle.net/karthick6891/pdL0kbqk/1/
Note: element in viewport code is reference from this link How to tell if a DOM element is visible in the current viewport?
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