I have discovered an issue with animations on the latest version of Firefox Quantum.
Upon loading a page with certain animated elements set to display: none;, when a script changes it to .display = "block";, some parts of the animation may be missed or not fully displayed at the beginning, especially if it's longer than a few seconds.
Check out the example in the code snippet below:
var anims = document.getElementsByClassName("anim"),
time = document.getElementById("time"),
interval = null;
function animate() {
for (var i = 0; i < anims.length; i++)
anims[i].style.display = "block";
}
function timer(sec) {
time.textContent = sec--;
interval = setInterval(function () {
time.textContent = sec >= 0 ? sec-- : clearInterval(interval) || "";
}, 1000);
}
// Trigger animation immediately after click
button0.addEventListener("click", animate);
// Trigger animation one second after click
button1.addEventListener("click", function () {
timer(1);
setTimeout(animate, 1000);
});
// Trigger animation two seconds after click
button2.addEventListener("click", function () {
timer(2);
setTimeout(animate, 2000);
});
// Trigger animation three seconds after click
button3.addEventListener("click", function () {
timer(3);
setTimeout(animate, 3000);
});
// Hide the divs
reset.addEventListener("click", function () {
for (var i = 0; i < anims.length; i++)
anims[i].style.display = "none";
});body {
font-family: arial;
}
body > div {
margin-bottom: 10px;
}
#result {
background-color: #e5f3ff;
height: 120px;
padding: 10px;
}
.anim {
display: none;
float: left;
margin: 10px;
width: 50px;
height: 50px;
border-radius: 5px;
animation: animate 1.5s;
}
#anim1 {
background-image: linear-gradient(120deg, #a1c4fd 0%, #c2e9fb 100%);
/* Only one iteration iteration (default) */
/* This one will not be animated */
}
#anim2 {
background-color: #fddb92;
animation-iteration-count: 3;
/* Three iterations */
/* Only one iteration will be seen */
}
#anim3 {
background-image: linear-gradient(45deg, #ff9a9e 0%, #fad0c4 99%, #fad0c4 100%);
animation-iteration-count: infinite;
/* Infinite */
/* No apparent issue */
}
@keyframes animate {
50% {
transform: translate(80%, 100%) rotate(-360deg);
}
}<div>
<span><strong>Reload the snippet</strong>
before clicking another button for viewing the issue
<br/><strong>Or,</strong>
<em>Reset</em> (display: "none") before clicking a button to view with no issue: </span>
</div>
<div>
<button id="button0">On click</button>
<button id="button1">1 sec timeout</button>
<button id="button2">2 sec timeout</button>
<button id="button3">3 sec timeout</button>
<button id="reset">Reset</button>
<span id="time"></span>
</div>
<div id="result">
<div id="anim1" class="anim"></div>
<div id="anim2" class="anim"></div>
<div id="anim3" class="anim"></div>
</div>Upon closer inspection, you'll notice that the infinite animation seems unaffected, while the other two clearly experience issues.
So, what's the solution to this problem?
Important:
- To witness this problem, make sure you are using Firefox Quantum.
- I have tested the same code snippet on Google Chrome and everything seems to be functioning correctly.