I was thinking. I know I can detect when a CSS animation has started, finished or is repeated by listening for the animationstart, animationiteration, animationend events (obviously we are missing browser prefixes there), for example:
document.getElementById('identifier')
.addEventListener("animationstart", function(){
// do something...
});
but I was wondering, is it possible to determine where we are are running a CSS animation, how for example with the following could I listen for when we are at 50% of the keyframe animation:
<!DOCTYPE html>
<html>
<head>
<style>
#animateDiv {
width: 100px;
height: 100px;
background-color: red;
position: relative;
animation-name: example;
animation-duration: 4s;
}
@keyframes example {
0% {background-color:red; left:0px; top:0px;}
25% {background-color:yellow; left:200px; top:0px;}
50% {background-color:blue; left:200px; top:200px;}
75% {background-color:green; left:0px; top:200px;}
100% {background-color:red; left:0px; top:0px;}
}
</style>
</head>
<body>
<div id="animateDiv"></div>
<script>
// what do I do here? How do I listen for the 50% event of the keyframes?
document.getElementById('animateDiv').addEventListener('animation at 50%?', function() {
console.log('got it');
})
</script>
</body>
</html>
I was thinking. I know I can detect when a CSS animation has started, finished or is repeated by listening for the animationstart, animationiteration, animationend events (obviously we are missing browser prefixes there), for example:
document.getElementById('identifier')
.addEventListener("animationstart", function(){
// do something...
});
but I was wondering, is it possible to determine where we are are running a CSS animation, how for example with the following could I listen for when we are at 50% of the keyframe animation:
<!DOCTYPE html>
<html>
<head>
<style>
#animateDiv {
width: 100px;
height: 100px;
background-color: red;
position: relative;
animation-name: example;
animation-duration: 4s;
}
@keyframes example {
0% {background-color:red; left:0px; top:0px;}
25% {background-color:yellow; left:200px; top:0px;}
50% {background-color:blue; left:200px; top:200px;}
75% {background-color:green; left:0px; top:200px;}
100% {background-color:red; left:0px; top:0px;}
}
</style>
</head>
<body>
<div id="animateDiv"></div>
<script>
// what do I do here? How do I listen for the 50% event of the keyframes?
document.getElementById('animateDiv').addEventListener('animation at 50%?', function() {
console.log('got it');
})
</script>
</body>
</html>
- I don't believe so. Unless you run a concurrent timer function alongside the animation. – Paulie_D Commented Jul 20, 2016 at 11:35
- 1 stackoverflow./questions/18006099/… – Andrew Bone Commented Jul 20, 2016 at 11:50
- 1 codepen.io/Zeaklous/pen/GwBJa – Afsar Commented Jul 20, 2016 at 11:54
- css-tricks./… – C3roe Commented Jul 20, 2016 at 14:03
3 Answers
Reset to default 5I don't know if you can get the exact keyframe from a CSS animation, but you can use some mathemathics to get it, like our mate Paulie_D suggested.
On your code, your animation is 4s length, so, the keyframe 50% of the annimation is after 2s:
//......
//when the animation starts....
setTimeout(function(){
//Enter your stuff here
}, 2000); //2 seconds delay, considering your animation length = 4s;
You can also use (needs jQuery):
$("#animated_element").bind("half_animation", function(){
//Ya stuff here
});
//.........
//When the animation starts...
setTimeout(function()
{
$("#animated_element").trigger("half_animation");
}, 2000);
Or:
$("#animated_element").bind("half_animation", function(){
once = 0;
setTimeout(function()
{
//Ya stuff here....
}, 2000)
});
//........
//When the animation starts
$("#animated_element").trigger("half_animation");
Here's my take on it.
- Get the animation duration.
- Sprinkle some mathematics on it like Vini suggested.
setTimeout()
Code:
const fn_runAtKeyframe = (DOMElement, keyframe, callback) => {
const animationDuration = window.getComputedStyle(DOMElement).animationDuration;
// animationDuration returns string, e.g. "5s" or "500ms", so need to parseInt()
// if it is in seconds, change it to milliseconds
let animationKeyframe
if (animationDuration.replace(/[0-9]/g, '') === "s") {
animationKeyframe = parseInt(animationDuration) * keyframe * 1000
} else {
animationKeyframe = parseInt(animationDuration) * keyframe
}
const doStuff = (e) => {
setTimeout(() => {
console.log(`Function "${callback.name}" will run at ${keyframe*100}% keyframe`)
callback();
}, animationKeyframe)
}
DOMElement.addEventListener("animationstart", doStuff);
// or use "animationiteration" depending on your usecase
}
Run it,
const animateDiv = document.querySelector("#animateDiv")
const keyframe = 0.5 // at 50% keyframe
const callback = () => {
// do stuff here...
};
fn_runAtKeyframe(animateDiv, keyframe, callback)
Like Vini said you have that chance, I make this for myself, you can change the "animation-play-state:" for any function you want.
//Animation pause at specific percentage, Example: pauseAnimationAt("myDiv",33,10)
function pauseAnimationAt(l,p,d){
percentage = p/d*1000;
function pauseAnimation(){
setTimeout(function(){ document.getElementById(l).style="animation-play-state: paused"; }, percentage);//l = Element ID, p = percentage when you wanna stopt animation, d = Duration of animation (Yes, you need to know that)
}
document.getElementById(l).addEventListener("animationstart", pauseAnimation());
}