HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <link
      rel="icon"
      href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>📺</text></svg>"
    />
    <title>How to add Picture-in-Picture to video controls</title>
  </head>
  <body>
    <h1>How to add Picture-in-Picture to video controls</h1>
    <button id="togglePipButton">Picture-in-Picture</button>
    <button id="toggleFakePipButton">Fake Picture-in-Picture</button>
    <video autoplay muted playsinline loop src="https://storage.googleapis.com/media-session/caminandes/short.mp4"></video>
  </body>
</html>

CSS


        :root {
  color-scheme: dark light;
}
html {
  box-sizing: border-box;
}
*,
*:before,
*:after {
  box-sizing: inherit;
}
body {
  margin: 1rem;
  font-family: system-ui, sans-serif;
}
button:before {
  content: "Enter ";
}
button.on:before {
  content: "Leave ";
}
video {
  display: block;
  margin-top: 10px;
  max-width: 100%;
}
video.fake-pip {
  position: fixed;
  z-index: 1000;
  bottom: 10px;
  right: 10px;
}

JS


        const video = document.querySelector('video');
const togglePipButton = document.querySelector('#togglePipButton');
const toggleFakePipButton = document.querySelector('#toggleFakePipButton');

togglePipButton.addEventListener("click", async (event) => {
  togglePipButton.disabled = true;
  try {
    if (video !== document.pictureInPictureElement) {
      await video.requestPictureInPicture();
    } else {
      await document.exitPictureInPicture();
    }
  } finally {
    togglePipButton.disabled = false;
  }
});

video.addEventListener("enterpictureinpicture", (event) => {
  togglePipButton.classList.add("on");
});

video.addEventListener("leavepictureinpicture", (event) => {
  togglePipButton.classList.remove("on");
});

/* Feature detection */
if ("pictureInPictureEnabled" in document) {
  // Hide fake PiP button if Picture-in-Picture is supported.
  toggleFakePipButton.hidden = true;
  // Set button ability depending on whether Picture-in-Picture can be used.
  setPipButton();
  video.addEventListener("loadedmetadata", setPipButton);
  video.addEventListener("emptied", setPipButton);
} else {
  // Hide button if Picture-in-Picture is not supported.
  togglePipButton.hidden = true;
}

function setPipButton() {
  togglePipButton.disabled =
    video.readyState === 0 ||
    !document.pictureInPictureEnabled ||
    video.disablePictureInPicture;
}

/* Fake Picture-in-Picture */
toggleFakePipButton.addEventListener("click", (event) => {
  toggleFakePipButton.classList.toggle("on");
  video.classList.toggle("fake-pip");
});