← Back toCSS Animation

Invalid input

Written byPhuoc Nguyen
30 Sep, 2022
The animation is often used to indicate an invalid input. It shakes the input for a while.
Press the Enter key to see the effect
The shaking animation moves the element to the left and right sides. It can be done by using the `translateX` function:
@keyframes shake {
to {
transform: translateX(0);

80% {
transform: translateX(-1rem);

60% {
transform: translateX(1rem);
To use the animation, we can add a simple `animation` style:
.input--invalid {
animation: shake 1s;
outline-color: #ef4444;
Let's assume that `inputEle` represents the input element. You can add the invalid CSS class created above anytime to indicate the input is invalid:

Remove the animation

If you want to remove the invalid state from the element when the animation completes, you can handle the `animationend` event:
inputEle.addEventListener('animationend', (e) => {
if (e.animationName === 'shake') {
Inside the event handler, you can use the `animationName` property to check which animation is completed. It's very useful in the case the element runs more than one animation at the same time.

Questions? 🙋

Do you have any questions? Not just about this specific post, but about any topic in front-end development that you'd like to learn more about? If so, feel free to send me a message on Twitter or send me an email. You can find them at the bottom of this page.
I have a long list of upcoming posts, but your questions or ideas for the next one will be my top priority. Let's learn together! Sharing knowledge is the best way to grow 🥷.

Recent posts ⚡

Newsletter 🔔

If you're into front-end technologies and you want to see more of the content I'm creating, then you might want to consider subscribing to my newsletter.
By subscribing, you'll be the first to know about new articles, products, and exclusive promotions.
Don't worry, I won't spam you. And if you ever change your mind, you can unsubscribe at any time.
Phước Nguyễn