使用 CSS 動畫

p {
  animation-duration: 3s;
  animation-name: slide-in;
  animation-iteration-count: infinite;
  animation-direction: alternate;
}

p {
  animation: 3s infinite alternate slide-in;
}

animation-name: fadeInOut, moveLeft300px, bounce;
animation-duration: 2.5s, 5s, 1s;
animation-iteration-count: 2, 1, 5;

animation-name: fadeInOut, moveLeft300px, bounce;
animation-duration: 3s;
animation-iteration-count: 1;

animation-name: fadeInOut, moveLeft300px, bounce;
animation-duration: 2.5s, 5s;
animation-iteration-count: 2, 1;

p {
  animation-duration: 3s;
  animation-name: slide-in;
}

@keyframes slide-in {
  from {
    translate: 150vw 0;
    scale: 200% 1;
  }

  to {
    translate: 0 0;
    scale: 100% 1;
  }
}

<p>
  The Caterpillar and Alice looked at each other for some time in silence: at
  last the Caterpillar took the hookah out of its mouth, and addressed her in a
  languid, sleepy voice.
</p>

@keyframes grow-shrink {
  25%,
  75% {
    scale: 100%;
  }

  50% {
    scale: 200%;
    color: magenta;
  }
}

p {
  animation-duration: 3s;
  animation-name: slide-in;
}
p span {
  display: inline-block;
  animation-duration: 3s;
  animation-name: grow-shrink;
}

@keyframes slide-in {
  from {
    translate: 150vw 0;
    scale: 200% 1;
  }

  to {
    translate: 0 0;
    scale: 100% 1;
  }
}

@keyframes grow-shrink {
  25%,
  75% {
    scale: 100%;
  }

  50% {
    scale: 200%;
    color: magenta;
  }
}

<p>
  The Caterpillar and <span>Alice</span> looked at each other for some time in
  silence: at last the Caterpillar took the hookah out of its mouth, and
  addressed her in a languid, sleepy voice.
</p>

p {
  animation-duration: 3s;
  animation-name: slide-in;
  animation-iteration-count: infinite;
}

@keyframes slide-in {
  from {
    translate: 150vw 0;
    scale: 200% 1;
  }

  to {
    translate: 0 0;
    scale: 100% 1;
  }
}

<p>
  The Caterpillar and Alice looked at each other for some time in silence: at
  last the Caterpillar took the hookah out of its mouth, and addressed her in a
  languid, sleepy voice.
</p>

p {
  animation-duration: 3s;
  animation-name: slide-in;
  animation-iteration-count: infinite;
  animation-direction: alternate;
}

@keyframes slide-in {
  from {
    translate: 150vw 0;
    scale: 200% 1;
  }

  to {
    translate: 0 0;
    scale: 100% 1;
  }
}

<p>
  The Caterpillar and Alice looked at each other for some time in silence: at
  last the Caterpillar took the hookah out of its mouth, and addressed her in a
  languid, sleepy voice.
</p>

.slide-in {
  animation-duration: 3s;
  animation-name: slide-in;
  animation-iteration-count: 3;
  animation-direction: alternate;
}

@keyframes slide-in {
  from {
    translate: 150vw 0;
    scale: 200% 1;
  }

  to {
    translate: 0 0;
    scale: 100% 1;
  }
}

const element = document.getElementById("watch-me");
element.addEventListener("animationstart", listener);
element.addEventListener("animationend", listener);
element.addEventListener("animationiteration", listener);

element.className = "slide-in";

function listener(event) {
  const l = document.createElement("li");
  switch (event.type) {
    case "animationstart":
      l.textContent = `Started: elapsed time is ${event.elapsedTime}`;
      break;
    case "animationend":
      l.textContent = `Ended: elapsed time is ${event.elapsedTime}`;
      break;
    case "animationiteration":
      l.textContent = `New loop started at time ${event.elapsedTime}`;
      break;
  }
  document.getElementById("output").appendChild(l);
}

<h1 id="watch-me">Watch me move</h1>
<p>
  This example shows how to use CSS animations to make <code>H1</code>
  elements move across the page.
</p>
<p>
  In addition, we output some text each time an animation event fires, so you
  can see them in action.
</p>
<ul id="output"></ul>

<p>
  Click anywhere on the screen or press any key to toggle the
  <code>&lt;div&gt;</code> between hidden and showing.
</p>

<div>
  This is a <code>&lt;div&gt;</code> element that animates between
  <code>display: none; opacity: 0</code> and
  <code>display: block; opacity: 1</code>. Neat, huh?
</div>

<p>
  This is another paragraph to show that <code>display: none;</code> is being
  applied and removed on the above <code>&lt;div&gt; </code>. If only its
  <code>opacity</code> was being changed, it would always take up the space in
  the DOM.
</p>

html {
  height: 100vh;
}

div {
  font-size: 1.6rem;
  padding: 20px;
  border: 3px solid red;
  border-radius: 20px;
  width: 480px;
  opacity: 0;
  display: none;
}

/* Animation classes */

div.fade-in {
  display: block;
  animation: fade-in 0.7s ease-in forwards;
}

div.fade-out {
  animation: fade-out 0.7s ease-out forwards;
}

/* Animation keyframes */

@keyframes fade-in {
  0% {
    opacity: 0;
    display: none;
  }

  100% {
    opacity: 1;
    display: block;
  }
}

@keyframes fade-out {
  0% {
    opacity: 1;
    display: block;
  }

  100% {
    opacity: 0;
    display: none;
  }
}

const divElem = document.querySelector("div");
const htmlElem = document.querySelector(":root");

htmlElem.addEventListener("click", showHide);
document.addEventListener("keydown", showHide);

function showHide() {
  if (divElem.classList[0] === "fade-in") {
    divElem.classList.remove("fade-in");
    divElem.classList.add("fade-out");
  } else {
    divElem.classList.remove("fade-out");
    divElem.classList.add("fade-in");
  }
}