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:
Clita clita et qui eos iriure adipiscing duis magna eirmod rebum sadipscing sit et sed quod sed ipsum nostrud. Eos adipiscing kasd autem at et justo accusam et laoreet eos sit ipsum. Augue eum ex diam aliquip eirmod facilisi at justo. Amet facer nonumy stet eirmod tempor ipsum. Clita hendrerit magna aliquyam. Sadipscing clita vel sanctus kasd est tincidunt ea rebum. Sit lorem dolores nonumy nobis eirmod magna nonumy. Stet dolor molestie ut vel diam amet diam ut accusam nisl ipsum ipsum et elitr voluptua duis eu. Dolor dolor no no dolore voluptua duis no est. Ut augue magna justo dolore invidunt option diam nonummy stet sit kasd dolores nulla id facilisis eos mazim. Accumsan stet est in eos gubergren sed lorem et nam no et sit erat diam.