// Find all YouTube videos var $allVideos = $("iframe[src^='//www.youtube.com']"), // The element that is fluid width $fluidEl = $("body"); // Figure out and save aspect ratio for each video $allVideos.each(function() { $(this) .data('aspectRatio', this.height / this.width) // and remove the hard coded width/height .removeAttr('height') .removeAttr('width'); }); // When the window is resized $(window).resize(function() { var newWidth = $fluidEl.width(); // Resize all videos according to their own aspect ratio $allVideos.each(function() { var $el = $(this); $el .width(newWidth) .height(newWidth * $el.data('aspectRatio')); }); // Kick off one resize to fix all videos on page load }).resize();