<script type="text/javascript" src="contextfree.js"></script>
<script type="text/javascript" src="cfdg.js"></script>
<script type="text/javascript">
    window.onload = function() {
        var src = '....'; // cfdg source
        var contextfree = new ContextFree(src, document.querySelector('canvas'));
        contextfree.render(function() {
            ... // called when rendering is done
        });
    };
</script>