https://www.davidgascon.com/wp-content/themes/egesto-lite/js/responsive-videos.js?ver=5.3.26

1(function() {
2    var fluid_vids = {
3        fluid_videos: function () {
4            var iframes = document.getElementsByTagName('iframe');
5            for (var i = 0; i < iframes.length; i++) {
6                var iframe = iframes[i],
7                    players = /www.youtube.com|player.vimeo.com/;
8                if (iframe.src.search(players) > 0) {
9                    var videoRatio = (iframe.height / iframe.width) * 100;
10                    iframe.style.position = 'absolute';
11                    iframe.style.top = '0';
12                    iframe.style.left = '0';
13                    iframe.width = '100%';
14                    iframe.height = '100%';
15                    var wrap = document.createElement('div');
16                    wrap.className = 'fluid-vids';
17                    wrap.style.width = '100%';
18                    wrap.style.position = 'relative';
19                    wrap.style.paddingTop = videoRatio + '%';
20                    var iframeParent = iframe.parentNode;
21                    iframeParent.insertBefore(wrap, iframe);
22                    wrap.appendChild(iframe);
23                }
24            }
25        }
26    };
27    fluid_vids.fluid_videos();
28})();