Playing background video

Hello, I'm using the Encore template, which won't allow me to play background video on every page of our website (thelab.org). For the code injection I'm using the below code, which seems to work for me on Chrome, Safari, and Firefox, but won't autoplay for other users on other computers. Any ideas on how to get this to play across the board?

  window.onload = function() {
    var iframe = document.createElement('iframe');
    iframe.id = "bg_video"
    iframe.style.cssText = "border:none;width:100vw;height:100vh;position:fixed;top:0px;left:0px;z-index:1;";
    iframe.src = "https://player.vimeo.com/video/362211620?autoplay=1&width=100" ;
    document.body.appendChild(iframe);
    resizeIframe();
    window.onresize = resizeIframe;
    var wrap = document.getElementById('outerWrapper');
    wrap.style.zIndex = '2';
};

Thank you for any help you can provide!