index.html

<!DOCTYPE html>
<html lang="en" manifest="offlinecache.manifest">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta charset="UTF-8">
    <title>Coderbunker Video</title>
</head>
<body style="background:#000;">
<video loop id='video' style="position:fixed;left:0;top:0;width:100vw;height: 100vh;" preload="auto">
    <source src="start.mp4" type="video/mp4">
</video>
<script>
    var video = document.getElementById("video");

    (function () {
        video.play();
        goFullscreen("video");
    })();

    function goFullscreen(id) {
        var element = document.getElementById(id);
        if (element.mozRequestFullScreen) {
            element.mozRequestFullScreen();
        } else if (element.webkitRequestFullScreen) {
            element.webkitRequestFullScreen();
        } else if (element.msRequestFullScreen) {
            element.msRequestFullScreen();
        }
    }


</script>
</body>
</html>