<div class="preloader">Loading</div>
.preloader {
position: fixed;
width: 100%;
height: 100%;
top: 0;
left: 0;
background: #000;
color: #fff;
z-index: 9999999;
}
$(document).ready(function() {
$('.preloader').fadeOut();
});
// либо
$(window).on('load', function () {
$('.preloader').fadeOut();
});
var videoArray = new Array();
videoArray[0]= 'url';
videoArray[1]= 'url';
videoArray[2]= 'url';
...
var rnd = Math.floor(Math.random()*(videoArray.length));
document.write('<video width="320" height="240" controls><source src="'+videoArray[rnd]+'" type="video/mp4"></video>'); // video
document.write('<iframe width="560" height="315" src="'+videoArray[rnd]+'" frameborder="0" allowfullscreen></iframe>'); // youtube