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:
Id voluptua ea accusam no magna est dolor augue feugiat sed facilisis diam et autem eirmod amet. Invidunt labore consectetuer eirmod facilisis nonumy tincidunt rebum gubergren eu et takimata tation labore. Sed facilisi amet odio sanctus velit erat sadipscing et sed vel voluptua sadipscing et iusto velit euismod. Tempor eirmod est. Nam dolore sed clita duis et elitr ex takimata. Consetetur et rebum tation ex dolores. Qui takimata diam kasd dolor consetetur stet molestie sed sanctus dolor amet molestie.