YouTube Embeds for Faster Page Load Speeds

It is easy to embed a YouTube video but you’ll be surprised to know how much extra weight that embedded YouTube video can add to your web pages. The browser has to download about half a Mb of extra JavaScript files (see screenshot) for rendering the YouTube video player alone. And these files are downloaded even if the visitor never plays the embedded video.

Copy-paste the following snippet anywhere in your web page where you would like the YouTube video to appear. Remember to replace VIDEO_ID with the actual ID of the YouTube video.

<div class="youtube-player" data-id="VIDEO_ID"></div>

We will not assign height and width since the video player will automatically occupy the width of the parent while the height is auto-calculated. You can paste multiple DIV blocks with different video IDs if you need to embed multiple videos on the same page.

Next, place the JavaScript anywhere in your web template. It finds all embedded videos on a web page and then replaces the DIV elements with the video thumbnails.

<script>

    /* Light YouTube Embeds by @labnol */
    /* Web: http://labnol.org/?p=27941 */

    document.addEventListener("DOMContentLoaded",
        function() {
            var div, n,
                v = document.getElementsByClassName("youtube-player");
            for (n = 0; n < v.length; n++) {
                div = document.createElement("div");
                div.setAttribute("data-id", v[n].dataset.id);
                div.innerHTML = labnolThumb(v[n].dataset.id);
                div.onclick = labnolIframe;
                v[n].appendChild(div);
            }
        });

    function labnolThumb(id) {
        var thumb = '<img src="https://i.ytimg.com/vi/ID/hqdefault.jpg">',
            play = '<div class="play"></div>';
        return thumb.replace("ID", id) + play;
    }

    function labnolIframe() {
        var iframe = document.createElement("iframe");
        var embed = "https://www.youtube.com/embed/ID?autoplay=1";
        iframe.setAttribute("src", embed.replace("ID", this.dataset.id));
        iframe.setAttribute("frameborder", "0");
        iframe.setAttribute("allowfullscreen", "1");
        this.parentNode.replaceChild(iframe, this);
    }

</script>

Finally, paste the CSS before the closing head tag of your web template.

This method will reduce the size of your web pages by 500 KB while making your site mobile friendly. You may refer to the annotated code to understanding how on-demand embedding works.

.youtube-player {
        position: relative;
        padding-bottom: 56.23%;
        /* Use 75% for 4:3 videos */
        height: 0;
        overflow: hidden;
        max-width: 100%;
        background: #000;
        margin: 5px;
    }

    .youtube-player iframe {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        z-index: 100;
        background: transparent;
    }

    .youtube-player img {
        bottom: 0;
        display: block;
        left: 0;
        margin: auto;
        max-width: 100%;
        width: 100%;
        position: absolute;
        right: 0;
        top: 0;
        border: none;
        height: auto;
        cursor: pointer;
        -webkit-transition: .4s all;
        -moz-transition: .4s all;
        transition: .4s all;
    }

    .youtube-player img:hover {
        -webkit-filter: brightness(75%);
    }

    .youtube-player .play {
        height: 72px;
        width: 72px;
        left: 50%;
        top: 50%;
        margin-left: -36px;
        margin-top: -36px;
        position: absolute;
        background: url("//i.imgur.com/TxzC70f.png") no-repeat;
        cursor: pointer;
    }

Leave a Comment