<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>RequestAnimationFrame</title>
</head>

<body>
  <div class="button-wrapper">
    <button onclick="onStart()">Start</button>
    <button onclick="onStop()">Stop</button>
  </div>
  <div id="container">
    <div class="frame"></div>
  </div>
</body>

</html>
body {
  width: 75%;
  margin: 5rem auto;
}
#container {
  display: flex;
  flex-wrap: wrap;
}
.button-wrapper {
  display: flex;
  justify-content: center;
  padding-block: 15px;
}
button {
  cursor: pointer;
  margin-right: 2rem;
  font-size: 1.2rem;
  padding: 10px 28px;
  border: none;
  border-radius: 4px;
}
button:nth-child(n) {
  box-shadow: inset 1px 1px 4px #3d7b3d;
  background-color: #6fe96f;
}
button:nth-child(2n) {
  box-shadow: inset 1px 1px 4px #df3030;
  background-color: #ffa2a2;
}
.frame {
  width: 15px;
  height: 15px;
  margin: 10px;
  border-radius: 50%;
  /*   transition: 1s; */
}
.frame:nth-child(n) {
  background-color: #ff00b1;
}
.frame:nth-child(2n) {
  background-color: #10bd10;
}
.frame:nth-child(3n) {
  background-color: #1095bd;
}
.frame:nth-child(4n) {
  background-color: #ffc645;
}
.frame:nth-child(5n) {
  background-color: #a645ff;
}

let frameID;
const getDiv = document.getElementsByClassName("frame");
const smoothAnimation = () => {
  getDiv[0].insertAdjacentHTML("afterend", "<div class='frame'></div>");
  frameID = requestAnimationFrame(smoothAnimation);
};

const onStart = () => {
  frameID = requestAnimationFrame(smoothAnimation);
};

const onStop = () => {
  cancelAnimationFrame(frameID);
};

External CSS

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External JavaScript

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