Develop Reference

how to use if statement inside an event listener? [duplicate]

I have a CSS3 animation that needs to be restarted on a click. It's a bar showing how much time is left. I'm using the scaleY(0) transform to create the effect.
Now I need to restart the animation by restoring the bar to scaleY(1) and let it go to scaleY(0) again.
My first attempt to set scaleY(1) failed because it takes the same 15 seconds to bring it back to full length. Even if I change the duration to 0.1 second, I would need to delay or chain the assignment of scaleY(0) to let the bar replenishment complete.
It feels too complicated for such a simple task.
I also found an interesting tip to restart the animation by removing the element from the document, and then re-inserting a clone of it:
http://css-tricks.com/restart-css-animation/
It works, but is there a better way to restart a CSS animation?
I'm using Prototype and Move.js, but I'm not restricted to them.

No need in timeout, use reflow to apply the change:
function reset_animation() {
var el = document.getElementById('animated');
el.style.animation = 'none';
el.offsetHeight; /* trigger reflow */
el.style.animation = null;
}
#animated {
position: absolute;
width: 50px; height: 50px;
background-color: black;
animation: bounce 3s ease-in-out infinite;
}
#keyframes bounce {
0% { left: 0; }
50% { left: calc( 100% - 50px ); }
100% { left: 0; }
}
<div id="animated"></div>
<button onclick="reset_animation()">Reset</button>

Just set the animation property via JavaScript to "none" and then set a timeout that changes the property to "", so it inherits from the CSS again.
Demo for Webkit here: http://jsfiddle.net/leaverou/xK6sa/
However, keep in mind that in real world usage, you should also include -moz- (at least).

#ZachB's answer about the Web Animation API seems like "right"™ way to do this, but unfortunately seems to require that you define your animations through JavaScript. However it caught my eye and I found something related that's useful:
Element.getAnimations() and Document.getAnimations()
The support for them is pretty good as of 2021.
In my case, I wanted to restart all the animations on the page at the same time, so all I had to do was this:
const replayAnimations = () => {
document.getAnimations().forEach((anim) => {
anim.cancel();
anim.play();
});
};
But in most cases people will probably want to select which animation they restart...
getAnimations returns a bunch of CSSAnimation and CSSTransition objects that look like this:
animationName: "fade"
currentTime: 1500
effect: KeyframeEffect
composite: "replace"
pseudoElement: null
target: path.line.yellow
finished: Promise {<fulfilled>: CSSAnimation}
playState: "finished"
ready: Promise {<fulfilled>: CSSAnimation}
replaceState: "active"
timeline: DocumentTimeline {currentTime: 135640.502}
# ...etc
So you could use the animationName and target properties to select just the animations you want (albeit a little circuitously).
EDIT
Here's a handy function that might be more compatible using just Document.getAnimations, with TypeScript thrown in for demonstration/fun:
// restart animations on a given dom element
const restartAnimations = (element: Element): void => {
for (const animation of document.getAnimations()) {
if (element.contains((animation.effect as KeyframeEffect).target)) {
animation.cancel();
animation.play();
}
}
};

Implement the animation as a CSS descriptor
Add the descriptor to an element to start the animation
Use a animationend event handler function to remove the descriptor when the animation completes so that it will be ready to be added again next time you want to restart the animation.
HTML
<div id="animatedText">
Animation happens here
</div>
<script>
function startanimation(element) {
element.classList.add("animateDescriptor");
element.addEventListener( "animationend", function() {
element.classList.remove("animateDescriptor");
} );
}
</script>
<button onclick="startanimation(
document.getElementById('animatedText') )">
Click to animate above text
</button>
CSS
#keyframes fadeinout {
from { color: #000000; }
25% {color: #0000FF; }
50% {color: #00FF00; }
75% {color: #FF0000; }
to { color : #000000; }
}
.animateDescriptor {
animation: fadeinout 1.0s;
}
Try it here: jsfiddle

If you have a class for CSS3 animation, for example .blink, then you can removeClass for some element and addClass for this element thought setTimeout with 1 millisecond by click.
$("#element").click(function(){
$(this).removeClass("blink");
setTimeout(function(){
$(this).addClass("blink);
},1 // it may be only 1 millisecond, but it's enough
});

You can also use display property, just set the display to none.
display:none;
and the change backs it to block (or any other property you want).
display:block;
using JavaScript.
and it will work amazingly.

The Animation API gives you full control over when and what to play, and is supported by all modern browsers (Safari 12.1+, Chrome 44+, Firefox 48+, Edge 79+) .
const effect = new KeyframeEffect(
el, // Element to animate
[ // Keyframes
{transform: "translateY(0%)"},
{transform: "translateY(100%)"}
],
{duration: 3000, direction: "alternate", easing: "linear"} // Keyframe settings
);
const animation = new Animation(effect, document.timeline);
animation.play();
Demo: https://jsfiddle.net/cstz9L8v/
References:
https://developer.mozilla.org/en-US/docs/Web/API/KeyframeEffect/KeyframeEffect
https://developer.mozilla.org/en-US/docs/Web/API/Animation

There is an answer on MDN, which is similar to the reflow approach:
<div class="box">
</div>
<div class="runButton">Click me to run the animation</div>
#keyframes colorchange {
0% { background: yellow }
100% { background: blue }
}
.box {
width: 100px;
height: 100px;
border: 1px solid black;
}
.changing {
animation: colorchange 2s;
}
function play() {
document.querySelector(".box").className = "box";
window.requestAnimationFrame(function(time) {
window.requestAnimationFrame(function(time) {
document.querySelector(".box").className = "box changing";
});
});
}

If you create two identical sets of keyframes, you can "restart" the animation by swapping between them:
function restart_animation(element) {
element.classList.toggle('alt')
}
#keyframes spin1 {
to { transform: rotateY(360deg); }
}
#keyframes spin2 {
to { transform: rotateY(360deg); }
}
.spin {
animation-name: spin1;
animation-duration: 2s;
}
.alt {
animation-name: spin2;
}
div {
width: 100px;
background: #8CF;
padding: 5px;
}
<div id=_square class=spin>
<button onclick="restart_animation(_square)">
Click to restart animation
</button>
</div>

On this page you can read about restarting the element animation: Restart CSS Animation (CSS Tricks)
Here is my example:
<head>
<style>
#keyframes selectss
{
0%{opacity: 0.7;transform:scale(1);}
100%{transform:scale(2);opacity: 0;}
}
</style>
<script>
function animation()
{
var elm = document.getElementById('circle');
elm.style.animation='selectss 2s ease-out';
var newone = elm.cloneNode(true);
elm.parentNode.replaceChild(newone, elm);
}
</script>
</head>
<body>
<div id="circle" style="height: 280px;width: 280px;opacity: 0;background-color: aqua;border-radius: 500px;"></div>
<button onclick="animation()"></button>
</body>
But if you want to you can just remove the element animation and then return it:
function animation()
{
var elm = document.getElementById('circle');
elm.style.animation='';
setTimeout(function () {elm.style.animation='selectss 2s ease-out';},10)
}

setInterval(() => {
$('#XMLID_640_').css('animation', 'none')
setTimeout(() => {
$('#XMLID_640_').css('animation', '')
}, 3000)
}, 13000)

Create a second "keyframe#" which restarts you animation, only problem with this you cannot set any animation properties for the restarting animation (it just kinda pops back)
HTML
<div class="slide">
Some text..............
<div id="slide-anim"></div>
</div><br>
<button onclick="slider()"> Animation </button>
<button id="anim-restart"> Restart Animation </button>
<script>
var animElement = document.getElementById('slide-anim');
document.getElementById('anim-restart').addEventListener("mouseup", restart_slider);
function slider() {
animElement.style.animationName = "slider"; // other animation properties are specified in CSS
}
function restart_slider() {
animElement.style.animation = "slider-restart";
}
</script>
CSS
.slide {
position: relative;
border: 3px black inset;
padding: 3px;
width: auto;
overflow: hidden;
}
.slide div:first-child {
position: absolute;
width: 100%;
height: 100%;
background: url(wood.jpg) repeat-x;
left: 0%;
top: 0%;
animation-duration: 2s;
animation-delay: 250ms;
animation-fill-mode: forwards;
animation-timing-function: cubic-bezier(.33,.99,1,1);
}
#keyframes slider {
to {left: 100%;}
}
#keyframes slider-restart {
to {left: 0%;}
}

Note that with React, clearing the animation like this, a codesandbox I found helps.
Example I used in my code:
function MyComponent() {
const [shouldTransition, setShouldTransition] = useState(true);
useEffect(() => {
setTimeout(() => {
// in my code, I change a background image here, and call this hook restart then animation,
// which first clears the animationName
setShouldTransition(false);
}, timeout * 1000);
}, [curr]);
useEffect(() => {
// then restore the animation name after it was cleared
if (shouldTransition === false) {
setShouldTransition(true);
}
}, [shouldTransition]);
return (
<div
ref={ref2}
style={{
animationName: shouldTransition ? "zoomin" : "",
}}
/>
);
}

I found out a simple solution today. Using the example provided in this answer, you can just append the element again to the body:
function resetAnimation() {
let element = document.getElementById('animated');
document.body.append(element);
}
#animated {
position: absolute;
width: 50px;
height: 50px;
background-color: LightSalmon;
animation: bounce 3s ease-in-out infinite;
}
#keyframes bounce {
0% {left: 0;}
50% {left: calc(100% - 50px);}
100% {left: 0;}
}
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<div id="animated"></div>
<button onclick="resetAnimation()">Reset</button>
</body>
</html>
Using Chrome's developer tools, the append does not actually append the element to the body and just replace it, probably because the same reference to the element is used.

Javascript / CSS animation is only played once [duplicate]

I have a CSS3 animation that needs to be restarted on a click. It's a bar showing how much time is left. I'm using the scaleY(0) transform to create the effect.
Now I need to restart the animation by restoring the bar to scaleY(1) and let it go to scaleY(0) again.
My first attempt to set scaleY(1) failed because it takes the same 15 seconds to bring it back to full length. Even if I change the duration to 0.1 second, I would need to delay or chain the assignment of scaleY(0) to let the bar replenishment complete.
It feels too complicated for such a simple task.
I also found an interesting tip to restart the animation by removing the element from the document, and then re-inserting a clone of it:
http://css-tricks.com/restart-css-animation/
It works, but is there a better way to restart a CSS animation?
I'm using Prototype and Move.js, but I'm not restricted to them.

No need in timeout, use reflow to apply the change:
function reset_animation() {
var el = document.getElementById('animated');
el.style.animation = 'none';
el.offsetHeight; /* trigger reflow */
el.style.animation = null;
}
#animated {
position: absolute;
width: 50px; height: 50px;
background-color: black;
animation: bounce 3s ease-in-out infinite;
}
#keyframes bounce {
0% { left: 0; }
50% { left: calc( 100% - 50px ); }
100% { left: 0; }
}
<div id="animated"></div>
<button onclick="reset_animation()">Reset</button>

Just set the animation property via JavaScript to "none" and then set a timeout that changes the property to "", so it inherits from the CSS again.
Demo for Webkit here: http://jsfiddle.net/leaverou/xK6sa/
However, keep in mind that in real world usage, you should also include -moz- (at least).

#ZachB's answer about the Web Animation API seems like "right"™ way to do this, but unfortunately seems to require that you define your animations through JavaScript. However it caught my eye and I found something related that's useful:
Element.getAnimations() and Document.getAnimations()
The support for them is pretty good as of 2021.
In my case, I wanted to restart all the animations on the page at the same time, so all I had to do was this:
const replayAnimations = () => {
document.getAnimations().forEach((anim) => {
anim.cancel();
anim.play();
});
};
But in most cases people will probably want to select which animation they restart...
getAnimations returns a bunch of CSSAnimation and CSSTransition objects that look like this:
animationName: "fade"
currentTime: 1500
effect: KeyframeEffect
composite: "replace"
pseudoElement: null
target: path.line.yellow
finished: Promise {<fulfilled>: CSSAnimation}
playState: "finished"
ready: Promise {<fulfilled>: CSSAnimation}
replaceState: "active"
timeline: DocumentTimeline {currentTime: 135640.502}
# ...etc
So you could use the animationName and target properties to select just the animations you want (albeit a little circuitously).
EDIT
Here's a handy function that might be more compatible using just Document.getAnimations, with TypeScript thrown in for demonstration/fun:
// restart animations on a given dom element
const restartAnimations = (element: Element): void => {
for (const animation of document.getAnimations()) {
if (element.contains((animation.effect as KeyframeEffect).target)) {
animation.cancel();
animation.play();
}
}
};

Implement the animation as a CSS descriptor
Add the descriptor to an element to start the animation
Use a animationend event handler function to remove the descriptor when the animation completes so that it will be ready to be added again next time you want to restart the animation.
HTML
<div id="animatedText">
Animation happens here
</div>
<script>
function startanimation(element) {
element.classList.add("animateDescriptor");
element.addEventListener( "animationend", function() {
element.classList.remove("animateDescriptor");
} );
}
</script>
<button onclick="startanimation(
document.getElementById('animatedText') )">
Click to animate above text
</button>
CSS
#keyframes fadeinout {
from { color: #000000; }
25% {color: #0000FF; }
50% {color: #00FF00; }
75% {color: #FF0000; }
to { color : #000000; }
}
.animateDescriptor {
animation: fadeinout 1.0s;
}
Try it here: jsfiddle

If you have a class for CSS3 animation, for example .blink, then you can removeClass for some element and addClass for this element thought setTimeout with 1 millisecond by click.
$("#element").click(function(){
$(this).removeClass("blink");
setTimeout(function(){
$(this).addClass("blink);
},1 // it may be only 1 millisecond, but it's enough
});

You can also use display property, just set the display to none.
display:none;
and the change backs it to block (or any other property you want).
display:block;
using JavaScript.
and it will work amazingly.

The Animation API gives you full control over when and what to play, and is supported by all modern browsers (Safari 12.1+, Chrome 44+, Firefox 48+, Edge 79+) .
const effect = new KeyframeEffect(
el, // Element to animate
[ // Keyframes
{transform: "translateY(0%)"},
{transform: "translateY(100%)"}
],
{duration: 3000, direction: "alternate", easing: "linear"} // Keyframe settings
);
const animation = new Animation(effect, document.timeline);
animation.play();
Demo: https://jsfiddle.net/cstz9L8v/
References:
https://developer.mozilla.org/en-US/docs/Web/API/KeyframeEffect/KeyframeEffect
https://developer.mozilla.org/en-US/docs/Web/API/Animation

There is an answer on MDN, which is similar to the reflow approach:
<div class="box">
</div>
<div class="runButton">Click me to run the animation</div>
#keyframes colorchange {
0% { background: yellow }
100% { background: blue }
}
.box {
width: 100px;
height: 100px;
border: 1px solid black;
}
.changing {
animation: colorchange 2s;
}
function play() {
document.querySelector(".box").className = "box";
window.requestAnimationFrame(function(time) {
window.requestAnimationFrame(function(time) {
document.querySelector(".box").className = "box changing";
});
});
}

If you create two identical sets of keyframes, you can "restart" the animation by swapping between them:
function restart_animation(element) {
element.classList.toggle('alt')
}
#keyframes spin1 {
to { transform: rotateY(360deg); }
}
#keyframes spin2 {
to { transform: rotateY(360deg); }
}
.spin {
animation-name: spin1;
animation-duration: 2s;
}
.alt {
animation-name: spin2;
}
div {
width: 100px;
background: #8CF;
padding: 5px;
}
<div id=_square class=spin>
<button onclick="restart_animation(_square)">
Click to restart animation
</button>
</div>

On this page you can read about restarting the element animation: Restart CSS Animation (CSS Tricks)
Here is my example:
<head>
<style>
#keyframes selectss
{
0%{opacity: 0.7;transform:scale(1);}
100%{transform:scale(2);opacity: 0;}
}
</style>
<script>
function animation()
{
var elm = document.getElementById('circle');
elm.style.animation='selectss 2s ease-out';
var newone = elm.cloneNode(true);
elm.parentNode.replaceChild(newone, elm);
}
</script>
</head>
<body>
<div id="circle" style="height: 280px;width: 280px;opacity: 0;background-color: aqua;border-radius: 500px;"></div>
<button onclick="animation()"></button>
</body>
But if you want to you can just remove the element animation and then return it:
function animation()
{
var elm = document.getElementById('circle');
elm.style.animation='';
setTimeout(function () {elm.style.animation='selectss 2s ease-out';},10)
}

setInterval(() => {
$('#XMLID_640_').css('animation', 'none')
setTimeout(() => {
$('#XMLID_640_').css('animation', '')
}, 3000)
}, 13000)

Create a second "keyframe#" which restarts you animation, only problem with this you cannot set any animation properties for the restarting animation (it just kinda pops back)
HTML
<div class="slide">
Some text..............
<div id="slide-anim"></div>
</div><br>
<button onclick="slider()"> Animation </button>
<button id="anim-restart"> Restart Animation </button>
<script>
var animElement = document.getElementById('slide-anim');
document.getElementById('anim-restart').addEventListener("mouseup", restart_slider);
function slider() {
animElement.style.animationName = "slider"; // other animation properties are specified in CSS
}
function restart_slider() {
animElement.style.animation = "slider-restart";
}
</script>
CSS
.slide {
position: relative;
border: 3px black inset;
padding: 3px;
width: auto;
overflow: hidden;
}
.slide div:first-child {
position: absolute;
width: 100%;
height: 100%;
background: url(wood.jpg) repeat-x;
left: 0%;
top: 0%;
animation-duration: 2s;
animation-delay: 250ms;
animation-fill-mode: forwards;
animation-timing-function: cubic-bezier(.33,.99,1,1);
}
#keyframes slider {
to {left: 100%;}
}
#keyframes slider-restart {
to {left: 0%;}
}

Note that with React, clearing the animation like this, a codesandbox I found helps.
Example I used in my code:
function MyComponent() {
const [shouldTransition, setShouldTransition] = useState(true);
useEffect(() => {
setTimeout(() => {
// in my code, I change a background image here, and call this hook restart then animation,
// which first clears the animationName
setShouldTransition(false);
}, timeout * 1000);
}, [curr]);
useEffect(() => {
// then restore the animation name after it was cleared
if (shouldTransition === false) {
setShouldTransition(true);
}
}, [shouldTransition]);
return (
<div
ref={ref2}
style={{
animationName: shouldTransition ? "zoomin" : "",
}}
/>
);
}

I found out a simple solution today. Using the example provided in this answer, you can just append the element again to the body:
function resetAnimation() {
let element = document.getElementById('animated');
document.body.append(element);
}
#animated {
position: absolute;
width: 50px;
height: 50px;
background-color: LightSalmon;
animation: bounce 3s ease-in-out infinite;
}
#keyframes bounce {
0% {left: 0;}
50% {left: calc(100% - 50px);}
100% {left: 0;}
}
<!DOCTYPE html>
<html>
<head>
</head>
<body>
<div id="animated"></div>
<button onclick="resetAnimation()">Reset</button>
</body>
</html>
Using Chrome's developer tools, the append does not actually append the element to the body and just replace it, probably because the same reference to the element is used.

Is it possible to access a specific moment in CSS animation?

I'm a frontend beginner studying Javascript and CSS animations.
I'm trying to make an element to blink according to a rythm (1 beat/second) and already synchronized the beat with the blink. I also would like to make this element to be clickable and act like a button to call a function when pressed. But this element must be clickable only in the beginning of the animation, when opacity is still >= 0.8.
I've tried to do that with visibility (hidden/visible), but it didn't work like I expected. So I'm trying it now with opacity.
Is it possible?
If I specify percentage (like 20%) to change opacity, what would be the syntax to access the percentage? element.style.opacity[??]
// Javascript code:
element.classList.add('blink');
// CSS code:
.blink {
animation-name: blink-animation;
animation-duration: 1000ms;
animation-timing-function: ease-in;
animation-iteration-count: infinite;
animation-fill-mode: forwards;
}
#keyframes blink-animation {
from { opacity: 1; }
to { opacity: 0; }
}

If you want to do it in css use pointer-events: none to prevent users from interacting with your element. When the animation is at 20% the opacity will be 0.8;
#keyframes blink-animation {
0% {
opacity: 1;
}
20% {
pointer-events: none;
}
100% {
opacity: 0;
}
}

You could control the blinking with transition and js instead of a keyframes animation. This way you have more fine grain control over the blinking and timing of music. You can also disable the button when not in a "blinky" state.
If you have any questions please ask.
const btn = document.querySelector("button");
const wait = ms => new Promise(r => setTimeout(r, ms));
(async () => {
while (true) {
btn.classList.add("blink");
btn.disabled = false;
await wait(1000);
btn.classList.remove("blink");
btn.disabled = true;
await wait(1000);
}
})();
btn.addEventListener("click", () => {
console.log("clicked!");
});
button {
transition: box-shadow 0.2s, opacity 0.2s;
opacity: 0.5;
}
button.blink {
box-shadow: 0 0 3px 2px pink;
opacity: 1;
}
<button disabled="true">Blinky</button>

CSS animation triggered through JS only plays every other click

I want to make a simple JavaScript onclick animation. My problem is that when I click onto the button, the animation is executed, but when I click again onto the button, nothing happens. On the third clicks the animation plays again. I want to make that, the animation plays at the second click.
Heres my code"
var anim = document.getElementById("anim");
anim.onclick = function highA() {
var willCheck = document.getElementById("contactId");
if (!willCheck.classList.contains("highAnim")) {
willCheck.classList.add("highAnim");
} else {
willCheck.classList.remove("highAnim");
}
}
#contactId { background: red;}
.highAnim {
background-color: var(--white);
animation-name: highcheck;
animation-duration: 0.35s;
animation-timing-function: ease-in-out;
}
#keyframes highcheck {
0% {transform: rotate(0);}
25% {transform: rotate(1deg);}
50% {transform: rotate(2deg);}
75% {transform: rotate(1deg);}
100% {transform: rotate(0);}
}
<a onclick="anim()" id="anim">Click</a><br><br>
<div id="contactId">Some Text</div>

The issue is because the first click adds the class and triggers the animation, yet the second (and every even numbered click) after that removes the class so nothing happens.
To fix this you can use the animationend event to remove the class automatically after the animation has ended. That way when you next click again the class is added to the element once more and the animation plays. Try this:
var anim = document.getElementById("anim");
var willCheck = document.getElementById("contactId");
anim.addEventListener('click', () => {
willCheck.classList.add("highAnim");
});
willCheck.addEventListener('animationend', () => {
willCheck.classList.remove("highAnim");
});
#contactId { background: red; }
.highAnim {
background-color: var(--white);
animation-name: highcheck;
animation-duration: 0.35s;
animation-timing-function: ease-in-out;
}
#keyframes highcheck {
0% { transform: rotate(0); }
50% { transform: rotate(2deg); }
100% { transform: rotate(0); }
}
<a id="anim">Click</a><br><br>
<div id="contactId">Some Text</div>
Note that I removed the 25% and 75% items in the animation as it's a linear motion from 0% to 50% and back again, so they are not needed. This also helps to make the animation smoother.

Another idea using animationiteration
var anim = document.getElementById("anim");
var willCheck = document.getElementById("contactId");
anim.addEventListener('click', () => {
willCheck.style.animationPlayState="running";
});
willCheck.addEventListener('animationiteration', () => {
willCheck.style.animationPlayState="paused";
});
#contactId {
background: red;
animation: highcheck 0.35s ease-in-out infinite paused;
}
#keyframes highcheck {
50% {
transform: rotate(2deg);
}
}
<a id="anim">Click</a><br><br>
<div id="contactId">Some Text</div>

webkit animation play state: how to start/stop animation on demand with javascript

I'm working on a game and just found out about -webkit-animation-play-state CSS attribute. I want certain text to show itself as a short animation, then hide and show when called again (in javascript).
I figured out how to start animation when I want to in javascript, but after its finished, the text stays on the screen, which I don't want to.
HTML:
<p id="INFO">
TEST
</p>
CSS:
#-webkit-keyframes pulse {
from {
opacity: 0.0;
font-size: 100%;
}
to {
opacity: 1.0;
font-size: 400%;
}
}
#INFO {
position: absolute;
left: 400px;
top: 200px;
-webkit-animation-name: pulse;
-webkit-animation-duration: 1s;
-webkit-animation-iteration-count: 1;
-webkit-animation-timing-function: ease-in-out;
-webkit-animation-play-state:paused;
visibility: hidden;
}
JS:
var INFO = document.getElementById("INFO");
INFO.innerHTML = "WRONG";
INFO.style.color = "RED";
INFO.style.webkitAnimationPlayState = "running";
INFO.style.visibility = "visible";
I read some questions/answers about -webkit-animation-play-state on this site, but none regarding the issue I am having.
One thing I read about was that animation goes to its default values when its ended. But my default values say that animation is "hidden" ? source: how to stop my webkit frame animation?
If anyone can point me in the right direction I'd be grateful.
If I was not clear enough, ask for more info please.
Thank you

For what you are trying to do, you don't need to use -webkit-animation-play-state.
Instead, try starting the animation by applying a class with the animation properties set. Then use a JavaScript event listener to remove the class once the animation finishes.
You should also keep the element hidden with opacity instead of visibility:hidden since you are manipulating the opacity in the animation.
CSS:
#-webkit-keyframes pulse {
from {
opacity: 0.0;
font-size: 100%;
}
to {
opacity: 1.0;
font-size: 400%;
}
}
#INFO {
opacity:0;
position: absolute;
left: 400px;
top: 200px;
}
.pulse {
-webkit-animation-name: pulse;
-webkit-animation-duration: 1s;
-webkit-animation-iteration-count: 1;
-webkit-animation-timing-function: ease-in-out;
}
JS:
var INFO = document.getElementById("INFO");
INFO.innerHTML = "WRONG";
INFO.style.color = "RED";
INFO.addEventListener('webkitAnimationEnd', function (e) {
this.classList.remove('pulse');
});
DEMO >> CodePen