JSFiddle - React, Tailwind, and code Playground

HTML

<video controls>
    <source type="video/webm" src="http://cdn.kaltura.org/apis/html5lib/kplayer-examples/media/bbb_trailer_360p.webm?a" />
    <source    src="http://cdn.kaltura.org/apis/html5lib/kplayer-examples/media/bbb_trailer_iphone270P.m4v"/>
    <source src="http://cdn.kaltura.org/apis/html5lib/kplayer-examples/media/bbb_trailer_400p.ogv" />
</video>
<span id="dimensions"></span>

CSS

#dimensions {
    display: block;
    font-weight: bold;
    color: #4c4c4c; 
}

JavaScript

$(function() {
    var video = document.getElementsByTagName("video")[0];
    var dimensions = document.getElementById("dimensions");
    dimensions.innerHTML = video.videoHeight + "x" + video.videoWidth;
});