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How to make an image fade in and another fade out with one button click?

I'm trying to fade in the blue square with the first click of the button. And then on the second click, the blue square fades out and the red one fades in.
As you can see when you test it, it doesn't work that way. I don't know where I am wrong and If anyone can show me how to fix it I'd appreciate it.
var currentscene = 0;
function next() {
currentscene++;
if (currentscene = 1) {
var element = document.getElementById("blue");
element.classList.add("fade-in");
}
if (currentscene = 2) {
var element = document.getElementById("blue");
element.classList.add("fade-out");
var element = document.getElementById("red");
element.classList.add("fade-in");
}
}
.squareblue {
height: 50px;
width: 50px;
top: 50px;
background-color: blue;
position: absolute;
opacity: 0;
animation-fill-mode: forwards;
}
.squarered {
height: 50px;
width: 50px;
top: 100px;
background-color: red;
position: absolute;
opacity: 0;
animation-fill-mode: forwards;
}
.fade-out {
animation: fadeOut ease 2s
}
#keyframes fadeOut {
0% {
opacity: 1;
}
100% {
opacity: 0;
}
}
.fade-in {
animation: fadeIn ease 2s
}
#keyframes fadeIn {
0% {
opacity: 0;
}
100% {
opacity: 1;
}
}
<div2 id="blue" class="squareblue"></div2>
<div2 id="red" class="squarered"></div2>
<button class="button" onclick="next()">next</button>

A few mistakes, and a few things to improve.
Inside your if conditionals, you were assigning the value of 1 and 2 to the variable currentscene instead of using the comparison operator ==. I added the remainder operator to be able to continue the loop indefinitely.
Instead of grabbing the element from the dom each loop, I just defined the elements at the top, and continued to reference the save variable.
instead of using a css keyframes animation, I used the css transition property to add animation to the changing of opacity.
If you have any questions, please ask 🚀
let currentscene = 0;
const blue = document.getElementById("blue");;
const red = document.getElementById("red");;
function next() {
currentscene++;
if (currentscene % 2 == 0) {
blue.classList.remove("opaque");
red.classList.add("opaque");
}
else if (currentscene % 2 == 1) {
red.classList.remove("opaque");
blue.classList.add("opaque");
}
}
.squareblue,
.squarered {
height: 50px;
width: 50px;
position: absolute;
opacity: 0;
animation-fill-mode: forwards;
transition: 1s;
}
.squareblue {
top: 50px;
background-color: blue;
}
.squarered {
top: 100px;
background-color: red;
}
.opaque {
opacity: 1;
}
button {user-select: none}
<div2 id="blue" class="squareblue"></div2>
<div2 id="red" class="squarered"></div2>
<button class="button" onclick="next()">next</button>

Toggling between classes keeps animation from going through, just skips to end

I'm trying to animate a hamburger menu by having the bottom and top line translate to the middle and then rotate into an X and want to reverse the animation when the X is clicked. Using jquery I'm toggling the class menu-open and menu-closed. When I remove the CSS for the menu-closed animation, it fires just fine but when I add the CSS back the animations just skip to the last frame. It forms what I want but just refuses to use the animation fully.
CSS
.navbar .mobile-menu.menu-open .line::before {
animation: menu-open-top 250ms linear forwards;
}
.navbar .mobile-menu.menu-open .line {
animation: menu-middle 250ms linear forwards;
}
.navbar .mobile-menu.menu-open .line::after {
animation: menu-open-bottom 250ms linear forwards;
}
.navbar .mobile-menu.menu-closed .line::before {
animation: menu-open-top 250ms linear reverse;
}
.navbar .mobile-menu.menu-closed .line {
animation: menu-middle 250ms linear reverse;
}
.navbar .mobile-menu.menu-closed .line::after {
animation: menu-open-bottom 250ms linear reverse;
}
Animation
#keyframes menu-open-top {
30% {
bottom: 0;
}
60% {
bottom: 0;
transform: rotate(0) translate(0);
}
100% {
transform: rotate(45deg) translate(5px, 5px);
visibility: visible;
}
}
#keyframes menu-middle {
40% {
visibility: hidden;
}
to {
visibility: hidden;
}
}
#keyframes menu-open-bottom {
30% {
top: 0;
}
60% {
top: 0;
transform: rotate(0) translate(0);
}
100% {
transform: rotate(-45deg) translate(6px, -6px);
visibility: visible;
}
}
JS
$(".mobile-menu").click(expandMenu);
function expandMenu() {
$(".primary-nav").toggleClass("menu-expand");
$(this).toggleClass("menu-open menu-closed");
}
I must be missing something or maybe I need to add new keyframes for the reverse animation but that feels like it would be unnecessary.
edit: here is the html as well
HTML
<div class="mobile-menu menu-closed">
<div class="line"></div>
</div>

Here's how to do it using simple prop value changes with careful timing. I guess it can be done using #keyframe animations as well, but I find them more difficult to follow/control/sync, at least in this case, considering it's (basically) a two-step animation.
document.querySelector('.mobile-menu').addEventListener('click', ({
target
}) => {
target.closest('.mobile-menu').classList.toggle('menu-open');
})
.mobile-menu {
--duration: 0.42s;
--size: 3rem;
--padding: 0.5rem;
--color: red;
--distance-timing: cubic-bezier(0.5, 0, 0.3, 1);
--rotation-timing: cubic-bezier(0.4, 0, 0.2, 1);
width: var(--size);
height: var(--size);
padding: var(--padding);
display: flex;
flex-direction: column;
justify-content: space-between;
cursor: pointer;
}
.mobile-menu * {
box-sizing: border-box;
}
.mobile-menu>div {
border: 1px solid var(--color);
height: 0;
width: 100%;
position: relative;
transform-origin: 50% 50%;
transition:
top calc(0.6 * var(--duration)) var(--distance-timing) calc(0.4 * var(--duration)),
bottom calc(0.6 * var(--duration)) var(--distance-timing) calc(0.4 * var(--duration)),
transform calc(0.8 * var(--duration)) var(--rotation-timing) 0s;
}
.mobile-menu> :nth-child(1) {
top: calc(var(--padding)/2);
}
.mobile-menu> :nth-child(3) {
bottom: calc(var(--padding)/2);
}
.mobile-menu.menu-open>div {
transition:
top calc(0.4 * var(--duration)) var(--distance-timing) 0s,
bottom calc(0.4 * var(--duration)) var(--distance-timing) 0s,
transform calc(0.8 * var(--duration)) var(--rotation-timing) calc(0.2 * var(--duration));
}
.mobile-menu.menu-open> :nth-child(1) {
top: calc(50% - 1px);
transform: rotate(0.125turn);
}
.mobile-menu.menu-open> :nth-child(2) {
transform: rotate(0.125turn);
}
.mobile-menu.menu-open> :nth-child(3) {
bottom: calc(50% - 1px);
transform: rotate(-0.125turn);
}
<div class="mobile-menu">
<div></div>
<div></div>
<div></div>
</div>
Same thing, in SCSS: https://jsfiddle.net/websiter/dybre2f9/
I've extracted the values into CSS vars, so it can be reused and modified with ease. Feel free to tweak it to your liking.
Note: the reason why I'm using bottom and top to animate the movement (and not translateY - which is slightly more performant) is because I wanted the two animations to be completely independent of each other, to allow me to play with various overlapping values and timing functions. What I've come up with doesn't respect the requirement 100% (as in, it slightly overlaps the rotation with the movement - but I'm doing it on purpose, as not overlapping them looks too mechanical). When overlapped, the entire animation seems more organic. It's like the button is alive and happy to have been asked to do the animation. Or maybe I'm just a bit crazy, I don't know...

Play new css animation seamlessly

I created a simple HTML game, which disappears under the screen when I click on a moving box.
However, the animation that disappears starts at the original location, not where it was clicked.
I think 0% of the remove #keyframes should have the location of the click, but I couldn't find a way
How shall I do it?
(function () {
const charactersGroup = document.querySelectorAll('.character');
const stage = document.querySelector('.stage')
const clickHandler = (e) => {
const target = e.target;
if (target.classList.contains('character')) {
target.classList.remove(`f${target.dataset.id}`);
target.classList.add('f0');
target.classList.add('remove');
setTimeout(() => { stage.removeChild(target) }, 2000);
}
}
stage.addEventListener('click', clickHandler);
}());
.stage {
overflow: hidden;
position: relative;
background: #eeeeaa;
width: 40vw;
height: 20vw;
}
#keyframes moving {
0% {
transform: translateX(0);
}
100% {
transform: translateX(30vw);
}
}
#keyframes remove {
0% {
transform: translate(0);
}
100% {
transform: translateY(60vw);
}
}
.character {
position: absolute;
width: 50px;
height: 50px;
background-repeat: no-repeat;
background-position: 50% 50%;
background-size: contain;
animation: moving infinite alternate;
}
.remove {
animation: remove 0.2s cubic-bezier(.68,-0.55,.27,1.55) forwards;
}
.f0 {
background-color: black;
animation-duration: 2s;
}
.f1 {
left: 5%;
bottom: 5%;
animation-duration: 2s;
background-color: red;
}
<div class="stage">
<div class="character f1" data-id="1"></div>
</div>

Change the first animation to consider left instead of translate then append both of them to the element initially and you simply toggle the animation-play-state when adding the remove class
(function() {
const charactersGroup = document.querySelectorAll('.character');
const stage = document.querySelector('.stage')
const clickHandler = (e) => {
const target = e.target;
if (target.classList.contains('character')) {
target.classList.add('remove');
setTimeout(() => {
stage.removeChild(target)
}, 2000);
}
}
stage.addEventListener('click', clickHandler);
}());
.stage {
overflow: hidden;
position: relative;
background: #eeeeaa;
width: 40vw;
height: 20vw;
}
#keyframes moving {
100% {
left:calc(95% - 50px);
}
}
#keyframes remove {
50% {
transform: translateY(-30vh);
}
100% {
transform: translateY(60vw);
}
}
.character {
position: absolute;
width: 50px;
height: 50px;
background:red;
left: 5%;
bottom: 5%;
animation:
moving 2s infinite alternate,
remove 1s cubic-bezier(.68, -0.55, .27, 1.55) forwards paused;
}
.remove {
animation-play-state:paused,running;
background: black;
}
<div class="stage">
<div class="character f1" data-id="1"></div>
</div>

If your use case is to deal with a lot of such boxes and complexity, it's better to go with handling everything with pure JS but I tried to make this work with minimal changes in JS and CSS.
I have added comments to the new JS lines.
Also taken the liberty to have a separate class with name moving for animation moving so that we can remove it on click.
(function () {
const charactersGroup = document.querySelectorAll('.character');
const stage = document.querySelector('.stage')
const clickHandler = (e) => {
const target = e.target;
if (target.classList.contains('character')) {
target.classList.remove(`f${target.dataset.id}`);
target.classList.add('f0');
// remove the moving animation
target.classList.remove('moving');
// Get offsetWidth which is the half of width to substract later while calculating left for the target i.e our box.
const offsetWidth = parseInt(getComputedStyle(target).width)/2;
// e.clientX gives us the x coordinate of the mouse pointer
// target.getBoundingClientRect().left gives us left position of the bounding rectangle and acts as a good offset to get the accurate left for our box.
target.style.left = `${e.clientX -target.getBoundingClientRect().left - offsetWidth}px`;
target.classList.add('remove');
setTimeout(() => { stage.removeChild(target) }, 2000);
}
}
stage.addEventListener('click', clickHandler);
}());
.stage {
overflow: hidden;
position: relative;
background: #eeeeaa;
width: 40vw;
height: 20vw;
}
#keyframes moving {
0% {
transform: translateX(0);
}
100% {
transform: translateX(30vw);
}
}
#keyframes remove {
0% {
transform: translate(0vh);
}
100% {
transform: translateY(60vw);
}
}
.character {
position: absolute;
width: 50px;
height: 50px;
background-repeat: no-repeat;
background-position: 50% 50%;
background-size: contain;
}
.moving{
animation: moving infinite alternate;
}
.remove {
animation: remove 0.2s cubic-bezier(.68,-0.55,.27,1.55) forwards;
}
.f0 {
background-color: black;
animation-duration: 2s;
}
.f1 {
left: 5%;
bottom: 5%;
animation-duration: 2s;
background-color: red;
}
<div class="stage">
<div class="character moving f1" data-id="1"></div>
</div>

How to stop and end a CSS transition with JavaScript using an image?

I have this problem where I am trying to implement a simple CSS transition with javascript, where when start button is pressed, it would move and stop depending on the duration of the keyframe and then when end is clicked, it would disappear and then again reappear when start is pressed with the same animation.
Does someone know what might be the issue here? And for some reason, when the transition is over, it jumps to the corner.
function add()
{
document.getElementById("myAnimation").classList.add("run-animation");
}
function remove()
{
document.getElementById("myAnimation").classList.remove("run-animation");
}
body{
background-color: "#4287f5";
}
#myAnimation
{
position:relative;
height: 40px;
width: 40p;
}
.run-animation
{
-webkit-animation: move 6s;
animation: move 6s;
}
#-webkit-keyframes move
{
0% {left: -200px;}
25% {left: 200px;}
50% {left: 100px;}
}
#keyframes move
{
0% {left: -200px;}
25% {left: 200px;}
50% {left: 100px;}
}
<button onclick="add()">Start</button>
<button onclick="remove()">End/Remove</button>
<div id="myAnimation" class="run-animation"><img src="https://cdn1.imggmi.com/uploads/2019/10/23/6e17286b0e01cf2775e6fa81a07d1ae3-full.png" /></div>

You said you want a "transition" but are using an animation. If you want a transition, use a transition.
"Yeah but how do I make it go farther than the end point?" [someone might say.]
Use a custom bezier-curve timing function where the ordinate will be outside the [0, 1] range. Doing so this will create a bouncing effect.
From there, it's easy to control the two states of your element since you only have to change one value.
#myAnimation {
height: 40px;
width: 40px;
background: red;
transform: translate(-40px, 0);
transition: transform 1.5s cubic-bezier(0, 0, 0.5, 3);
}
:checked ~ #myAnimation {
transform: translate(100px, 0);
}
body{ margin:0; }
<input type="checkbox" id="check"><label for="check">show elem</label>
<div id="myAnimation"></div>
Note: In the above example I used transform instead of your original left because for performance reasons that should be the preferred way, but that will work with any animatable property.
Also, I used a simple checkbox as the control, but you can keep your button + js to toggle a class, that will do just the same.

That is probably because you are not defining how your element should look when it is not animated. You can set a display:none; on it by default and then a display:block; during the animation. Here is an example:
function add() {
document.getElementById("myAnimation").classList.add("run-animation");
}
function remove() {
document.getElementById("myAnimation").classList.remove("run-animation");
}
body {
background-color: "#4287f5";
}
#myAnimation {
position: relative;
/*
Hide the element if it is not animated
*/
display: none;
height: 40px;
width: 40p;
}
#myAnimation.run-animation {
-webkit-animation: move 6s;
animation: move 6s;
/*
Show the element if it is animated
*/
display: block;
}
#-webkit-keyframes move {
0% {
left: -200px;
}
25% {
left: 200px;
}
50% {
left: 100px;
}
}
#keyframes move {
0% {
left: -200px;
}
25% {
left: 200px;
}
50% {
left: 100px;
}
}
<button onclick="add()">Start</button>
<button onclick="remove()">End/Remove</button>
<div id="myAnimation" class="run-animation"><img src="https://cdn1.imggmi.com/uploads/2019/10/23/6e17286b0e01cf2775e6fa81a07d1ae3-full.png" /></div>

maybe this can help
function add()
{
document.getElementById("myAnimation").classList.add("run-animation");
}
function remove()
{
document.getElementById("myAnimation").classList.remove("run-animation");
}
body{
background-color: "#4287f5";
}
#myAnimation
{
position:relative;
height: 40px;
width: 40p;
left: 0;
opacity: 1;
}
.run-animation
{
-webkit-animation: move 6s;
animation: move 6s;
animation-fill-mode: forwards;
}
#-webkit-keyframes move
{
0% {left: 0;}
25% {left: 200px;opacity: 1;}
50% {left: 100px;opacity: 0;}
80% {left: 0; opacity: 0;}
100% {left: 0; opacity: 1;}
}
#keyframes move
{
0% {left: 0;}
25% {left: 200px;opacity: 1;}
50% {left: 100px;opacity: 0;}
80% {left: 0; opacity: 0;
100% {left: 0; opacity: 1;
}
<button onclick="add()">Start</button>
<button onclick="remove()">End/Remove</button>
<div id="myAnimation" class="run-animation"><img src="https://cdn1.imggmi.com/uploads/2019/10/23/6e17286b0e01cf2775e6fa81a07d1ae3-full.png" /></div>

Trigger CSS Animations in JavaScript

I don't know how to use JQuery, so I need a method which could trigger an animation using JavaScript only.
I need to call/trigger CSS Animation when the user scrolls the page.
function start() {
document.getElementById('logo').style.animation = "anim 2s 2s forward";
document.getElementById('earthlogo').style.animation = "anim2 2s 2s forward";
}
* {
margin: 0px;
}
#logo {
position: fixed;
top: 200px;
height: 200px;
width: 1000px;
left: 5%;
z-index: 4;
opacity: 0.8;
}
#earthlogo {
position: fixed;
top: 200px;
height: 120px;
align-self: center;
left: 5%;
margin-left: 870px;
margin-top: 60px;
z-index: 4;
opacity: 0.9;
}
#keyframes anim {
50% {
filter: blur(10px);
transform: rotate(-15deg);
box-shadow: 0px 0px 10px 3px;
}
100% {
height: 100px;
width: 500px;
left: 10px;
top: 10px;
box-shadow: 0px 0px 15px 5px rgba(0, 0, 0, 0.7);
background-color: rgba(0, 0, 1, 0.3);
opacity: 0.7;
}
}
#keyframes anim2 {
50% {
filter: blur(40px);
transform: rotate(-15deg);
}
100% {
height: 60px;
width: 60px;
left: 10px;
top: 10px;
margin-left: 435px;
margin-top: 30px;
opacity: 0.8;
}
}
#backstar {
position: fixed;
width: 100%;
z-index: 1;
}
#earth {
position: absolute;
width: 100%;
z-index: 2;
top: 300px;
}
<img src="logo.png" id="logo" onclick="start();">
<img src="earthlogo.gif" id="earthlogo" onscroll="start();">
<img src="earth.png" id="earth">
<img src="stars.jpg" id="backstar">

The simplest method to trigger CSS animations is by adding or removing a class - how to do this with pure Javascript you can read here:
How do I add a class to a given element?
If you DO use jQuery (which should really be easy to learn in basic usage) you do it simply with addClass / removeClass.
All you have to do then is set a transition to a given element like this:
.el {
width:10px;
transition: all 2s;
}
And then change its state if the element has a class:
.el.addedclass {
width:20px;
}
Note: This example was with transition. But for animations its the same: Just add the animation on the element which has a class on it.
There is a similar question here: Trigger a CSS keyframe animation via scroll

This is how you can use vanilla JavaScript to change/trigger an animation associated with an HTML element.
First, you define your animations in CSS.
#keyframes spin1 { 100% { transform:rotate(360deg); } }
#keyframes spin2 { 100% { transform:rotate(-360deg); } }
#keyframes idle { 100% {} }
Then you use javascript to switch between animations.
document.getElementById('yourElement').style.animation="spin2 4s linear infinite";
Note: 'yourElement' is the target HTML element that you wish to
animate.
For example: <div id="yourElement"> ... </div>

Adding and removing the animation class does not work in a function. The delay is simply too little. As suggested by this article you can request the browser to reflow and then add the class. The delay isn't an issue in that case. Hence, you can use this code:
element.classList.remove("animation")
element.offsetWidth
element.classList.add("animation")
The best thing is, this works everywhere. All credit goes to the article.

A more idiomatic solution is to use the Web Animations API.
Here is the example from MDN:
document.getElementById("alice").animate(
[
{ transform: 'rotate(0) translate3D(-50%, -50%, 0)', color: '#000' },
{ color: '#431236', offset: 0.3 },
{ transform: 'rotate(360deg) translate3D(-50%, -50%, 0)', color: '#000' }
], {
duration: 3000,
iterations: Infinity
}
);
OP's example:
document.getElementById('logo').animate(
[
{},
{
filter: 'blur(10px)',
transform: 'rotate(-15deg)',
box-shadow: '0px 0px 10px 3px',
},
{
height: '100px',
width: '500px',
left: '10px',
top: '10px',
box-shadow: '0px 0px 15px 5px rgba(0, 0, 0, 0.7)',
background-color: 'rgba(0, 0, 1, 0.3)',
opacity: '0.7',
},
],
{
duration: 2000,
delay: 2000,
fill: 'forwards',
},
)
At the time of writing, it's supported in all major browsers except IE.
Supported browsers

I have a similar problem.
The best answer didn’t work for me, but when I added the delay it worked.
The following is my solution.
CSS
.circle_ani1,
.circle_ani2 {
animation-duration: 1s;
animation-iteration-count: 1;
}
.circle_ani1 {
animation-name: circle1;
}
.circle_ani2 {
animation-name: circle2;
}
JS
let temp_circle1 = $('.TimeCountdown_circle1').removeClass('circle_ani1');
let temp_circle2 = $('.TimeCountdown_circle2').removeClass('circle_ani2');
window.setTimeout(function() {
temp_circle1.addClass('circle_ani1');
temp_circle2.addClass('circle_ani2');
}, 50);

Vanilla JS version
document.getElementById('logo').classList.add("anim");
document.getElementById('earthlogo').classList.add("anim2");

You could use CSS to hide the image / animation and show when the user scrolls. This would work like this:
CSS:
div {
border: 1px solid black;
width: 200px;
height: 100px;
overflow: scroll;
}
#demo{
display: none;
}
HTML:
<div id="myDIV"> </div>
<div id="demo">
<img src="earthlogo.gif" id="earthlogo" alt="Thanks for scrolling. Now you see me">
</div>
Your javascript just needs to include an eventListener to call the function which triggers the display of your animation.
JS:
document.getElementById("myDIV").addEventListener("scroll", start);
function start() {
document.getElementById('demo').style.display='block';
}

You could use animation-play-state (Mdn docs) like this
element.style.animationPlayState = "paused/running"
Code snippet:
function play() {
document.getElementById("div").style.animationPlayState = "running";
}
function pause() {
document.getElementById("div").style.animationPlayState = "paused";
}
.animation {
width: 50px;
height: 50px;
background-color: red;
position: relative;
animation-name: example;
animation-duration: 2s;
animation-play-state: paused;
animation-iteration-count: infinite;
}
#keyframes example {
0% {
background-color: red;
left: 0px;
top: 0px;
}
25% {
background-color: yellow;
left: 50px;
top: 0px;
}
50% {
background-color: blue;
left: 50px;
top: 50px;
}
75% {
background-color: green;
left: 0px;
top: 50px;
}
100% {
background-color: red;
left: 0px;
top: 0px;
}
}
<button onclick="play()">Play</button>
<button onclick="pause()">Pause</button><br><br>
<div id="div" class="animation"></div>

Here's the main code:
HTML:
<img id="myImg">
CSS:
#myImg {
//properties
animation: animate 2s linear infinite //infinite is important!
}
#keyframes animate {
//animation base
}
JS:
document.getElementById("myImg").style.webkitAnimationPlayState = "paused";
window.addEventListener("scroll", function() {
document.getElementById("myImg").style.webkitAnimationPlayState = "running";
setTimeout(function() {
document.getElementById("myImg").style.webkitAnimationPlayState = "paused";
}, 2000);
});

If you want Animations i recommend you create a CSS class which you toggle on a Condition whit JS:
CSS
.animation {
animation: anim 2s ease infinite;
transition: .2s
}
JS
// Select your Element
$element.document.querySelector(".yourElement");
$element.addEventListner('click', () => {
$element.classList.toggle("animation")
})