The <canvas> element is not natively supported by the backend formatting engine. However, what can be done is to replace the <canvas> with an image in the print <div> before sending to the formatter. There are a few Javascript drawn <canvas> elements on this page. They are processed to the output by the xepOnine.jgPlugin.js Javascript by converting them on-the-fly to image format.
This is a second <canvas> element on the page:
Ut vero molestie aliquam. Ea ut sit sea velit aliquyam aliquyam luptatum et sanctus eu dolores suscipit eu takimata aliquyam. Et accusam tempor amet stet ipsum amet eros eos vel adipiscing dolores tempor. Nonumy ipsum diam suscipit dolor lorem labore ex nisl nulla. Est wisi mazim cum lorem accumsan dolor.