SO - http://stackoverflow.com/q/10295746/1055987

By JFK

HTML

<script src="http://fancyapps.com/fancybox/source/jquery.fancybox.js"></script>
<link rel="stylesheet" href="http://fancyapps.com/fancybox/source/jquery.fancybox.css">
<a class="fancybox fancybox.iframe" data-width="1287" data-height="720" href="http://jsfiddle.net">HD 1287x720</a>
<br />
<a class="fancybox fancybox.iframe" data-width="640" data-height="360" href="http://jsfiddle.net">SD 640x360</a>

JavaScript

$('.fancybox').fancybox({
    fitToView: false,
    autoSize: false,
    afterLoad: function () {
        this.width = $(this.element).data("width");
        this.height = $(this.element).data("height");
    }
});