diff --git a/docs/css/lite-yt-embed.css b/docs/css/lite-yt-embed.css
new file mode 100644
index 0000000..6f3d3e5
--- /dev/null
+++ b/docs/css/lite-yt-embed.css
@@ -0,0 +1,97 @@
+lite-youtube {
+ background-color: #000;
+ position: relative;
+ display: block;
+ contain: content;
+ background-position: center center;
+ background-size: cover;
+ cursor: pointer;
+ max-width: 720px;
+}
+
+/* gradient */
+lite-youtube::before {
+ content: attr(data-title);
+ display: block;
+ position: absolute;
+ top: 0;
+ /* Pixel-perfect port of YT's gradient PNG, using https://github.com/bluesmoon/pngtocss plus optimizations */
+ background-image: linear-gradient(180deg, rgb(0 0 0 / 67%) 0%, rgb(0 0 0 / 54%) 14%, rgb(0 0 0 / 15%) 54%, rgb(0 0 0 / 5%) 72%, rgb(0 0 0 / 0%) 94%);
+ height: 99px;
+ width: 100%;
+ font-family: "YouTube Noto", Roboto, Arial, Helvetica, sans-serif;
+ color: hsl(0deg 0% 93.33%);
+ text-shadow: 0 0 2px rgba(0, 0, 0, .5);
+ font-size: 18px;
+ padding: 25px 20px;
+ overflow: hidden;
+ white-space: nowrap;
+ text-overflow: ellipsis;
+ box-sizing: border-box;
+}
+
+lite-youtube:hover::before {
+ color: white;
+}
+
+/* responsive iframe with a 16:9 aspect ratio
+ thanks https://css-tricks.com/responsive-iframes/
+*/
+lite-youtube::after {
+ content: "";
+ display: block;
+ padding-bottom: calc(100% / (16 / 9));
+}
+
+lite-youtube>iframe {
+ width: 100%;
+ height: 100%;
+ position: absolute;
+ top: 0;
+ left: 0;
+ border: 0;
+}
+
+/* play button */
+lite-youtube>.lty-playbtn {
+ display: block;
+ /* Make the button element cover the whole area for a large hover/click target… */
+ width: 100%;
+ height: 100%;
+ /* …but visually it's still the same size */
+ background: no-repeat center/68px 48px;
+ /* YT's actual play button svg */
+ background-image: url('data:image/svg+xml;utf8,');
+ position: absolute;
+ cursor: pointer;
+ z-index: 1;
+ filter: grayscale(100%);
+ transition: filter .1s cubic-bezier(0, 0, 0.2, 1);
+ border: 0;
+}
+
+lite-youtube:hover>.lty-playbtn,
+lite-youtube .lty-playbtn:focus {
+ filter: none;
+}
+
+/* Post-click styles */
+lite-youtube.lyt-activated {
+ cursor: unset;
+}
+
+lite-youtube.lyt-activated::before,
+lite-youtube.lyt-activated>.lty-playbtn {
+ opacity: 0;
+ pointer-events: none;
+}
+
+.lyt-visually-hidden {
+ clip: rect(0 0 0 0);
+ clip-path: inset(50%);
+ height: 1px;
+ overflow: hidden;
+ position: absolute;
+ white-space: nowrap;
+ width: 1px;
+}
diff --git a/docs/eleventy.config.js b/docs/eleventy.config.js
index c7ab6bd..c7cfe8f 100644
--- a/docs/eleventy.config.js
+++ b/docs/eleventy.config.js
@@ -74,7 +74,7 @@ module.exports = function (eleventyConfig) {
eleventyConfig.setLibrary('md', markdownLibrary)
eleventyConfig.setServerOptions({
- watch: ['_sites/**/*.js'],
+ watch: ['_site/**/*.js'],
})
return {
diff --git a/docs/js/lite-yt-embed.js b/docs/js/lite-yt-embed.js
new file mode 100644
index 0000000..3891c80
--- /dev/null
+++ b/docs/js/lite-yt-embed.js
@@ -0,0 +1,238 @@
+/**
+ * A lightweight youtube embed. Still should feel the same to the user, just MUCH faster to initialize and paint.
+ *
+ * Thx to these as the inspiration
+ * https://storage.googleapis.com/amp-vs-non-amp/youtube-lazy.html
+ * https://autoplay-youtube-player.glitch.me/
+ *
+ * Once built it, I also found these:
+ * https://github.com/ampproject/amphtml/blob/master/extensions/amp-youtube (👍👍)
+ * https://github.com/Daugilas/lazyYT
+ * https://github.com/vb/lazyframe
+ */
+class LiteYTEmbed extends HTMLElement {
+ connectedCallback() {
+ this.videoId = this.getAttribute('videoid');
+
+ let playBtnEl = this.querySelector('.lty-playbtn');
+ // A label for the button takes priority over a [playlabel] attribute on the custom-element
+ this.playLabel = (playBtnEl && playBtnEl.textContent.trim()) || this.getAttribute('playlabel') || 'Play';
+
+ this.dataset.title = this.getAttribute('title') || "";
+
+ /**
+ * Lo, the youtube poster image! (aka the thumbnail, image placeholder, etc)
+ *
+ * See https://github.com/paulirish/lite-youtube-embed/blob/master/youtube-thumbnail-urls.md
+ */
+ if (!this.style.backgroundImage) {
+ this.style.backgroundImage = `url("https://i.ytimg.com/vi/${this.videoId}/hqdefault.jpg")`;
+ this.upgradePosterImage();
+ }
+
+ // Set up play button, and its visually hidden label
+ if (!playBtnEl) {
+ playBtnEl = document.createElement('button');
+ playBtnEl.type = 'button';
+ playBtnEl.classList.add('lty-playbtn');
+ this.append(playBtnEl);
+ }
+ if (!playBtnEl.textContent) {
+ const playBtnLabelEl = document.createElement('span');
+ playBtnLabelEl.className = 'lyt-visually-hidden';
+ playBtnLabelEl.textContent = this.playLabel;
+ playBtnEl.append(playBtnLabelEl);
+ }
+
+ this.addNoscriptIframe();
+
+ // for the PE pattern, change anchor's semantics to button
+ if (playBtnEl.nodeName === 'A') {
+ playBtnEl.removeAttribute('href');
+ playBtnEl.setAttribute('tabindex', '0');
+ playBtnEl.setAttribute('role', 'button');
+ // fake button needs keyboard help
+ playBtnEl.addEventListener('keydown', e => {
+ if (e.key === 'Enter' || e.key === ' ') {
+ e.preventDefault();
+ this.activate();
+ }
+ });
+ }
+
+ // On hover (or tap), warm up the TCP connections we're (likely) about to use.
+ this.addEventListener('pointerover', LiteYTEmbed.warmConnections, { once: true });
+ this.addEventListener('focusin', LiteYTEmbed.warmConnections, { once: true });
+
+ // Once the user clicks, add the real iframe and drop our play button
+ // TODO: In the future we could be like amp-youtube and silently swap in the iframe during idle time
+ // We'd want to only do this for in-viewport or near-viewport ones: https://github.com/ampproject/amphtml/pull/5003
+ this.addEventListener('click', this.activate);
+
+ // Chrome & Edge desktop have no problem with the basic YouTube Embed with ?autoplay=1
+ // However Safari desktop and most/all mobile browsers do not successfully track the user gesture of clicking through the creation/loading of the iframe,
+ // so they don't autoplay automatically. Instead we must load an additional 2 sequential JS files (1KB + 165KB) (un-br) for the YT Player API
+ // TODO: Try loading the the YT API in parallel with our iframe and then attaching/playing it. #82
+ this.needsYTApi = this.hasAttribute("js-api") || navigator.vendor.includes('Apple') || navigator.userAgent.includes('Mobi');
+ }
+
+ /**
+ * Add a to the head
+ */
+ static addPrefetch(kind, url, as) {
+ const linkEl = document.createElement('link');
+ linkEl.rel = kind;
+ linkEl.href = url;
+ if (as) {
+ linkEl.as = as;
+ }
+ document.head.append(linkEl);
+ }
+
+ /**
+ * Begin pre-connecting to warm up the iframe load
+ * Since the embed's network requests load within its iframe,
+ * preload/prefetch'ing them outside the iframe will only cause double-downloads.
+ * So, the best we can do is warm up a few connections to origins that are in the critical path.
+ *
+ * Maybe `` would work, but it's unsupported: http://crbug.com/593267
+ * But TBH, I don't think it'll happen soon with Site Isolation and split caches adding serious complexity.
+ */
+ static warmConnections() {
+ if (LiteYTEmbed.preconnected) return;
+
+ // The iframe document and most of its subresources come right off youtube.com
+ LiteYTEmbed.addPrefetch('preconnect', 'https://www.youtube-nocookie.com');
+ // The botguard script is fetched off from google.com
+ LiteYTEmbed.addPrefetch('preconnect', 'https://www.google.com');
+
+ // Not certain if these ad related domains are in the critical path. Could verify with domain-specific throttling.
+ LiteYTEmbed.addPrefetch('preconnect', 'https://googleads.g.doubleclick.net');
+ LiteYTEmbed.addPrefetch('preconnect', 'https://static.doubleclick.net');
+
+ LiteYTEmbed.preconnected = true;
+ }
+
+ fetchYTPlayerApi() {
+ if (window.YT || (window.YT && window.YT.Player)) return;
+
+ this.ytApiPromise = new Promise((res, rej) => {
+ var el = document.createElement('script');
+ el.src = 'https://www.youtube.com/iframe_api';
+ el.async = true;
+ el.onload = _ => {
+ YT.ready(res);
+ };
+ el.onerror = rej;
+ this.append(el);
+ });
+ }
+
+ /** Return the YT Player API instance. (Public L-YT-E API) */
+ async getYTPlayer() {
+ if (!this.playerPromise) {
+ await this.activate();
+ }
+
+ return this.playerPromise;
+ }
+
+ async addYTPlayerIframe() {
+ this.fetchYTPlayerApi();
+ await this.ytApiPromise;
+
+ const videoPlaceholderEl = document.createElement('div')
+ this.append(videoPlaceholderEl);
+
+ const paramsObj = Object.fromEntries(this.getParams().entries());
+
+ this.playerPromise = new Promise(resolve => {
+ let player = new YT.Player(videoPlaceholderEl, {
+ width: '100%',
+ videoId: this.videoId,
+ playerVars: paramsObj,
+ events: {
+ 'onReady': event => {
+ event.target.playVideo();
+ resolve(player);
+ }
+ }
+ });
+ });
+ }
+
+ // Add the iframe within