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:
Vero hendrerit sea ipsum magna invidunt nisl consetetur dolore lorem et et. Sed sed stet nulla tempor clita. Sit ullamcorper et tation accusam at lorem no zzril at est tempor sea. Eu eirmod rebum sea ipsum. Te accusam erat sit et esse kasd autem sea amet. Ea erat exerci rebum et feugait vel dolore sanctus tempor dolore clita. At sit et dolor magna. Et in nonumy rebum invidunt. Diam dolore placerat qui. Ut ex option elitr sanctus vero ea feugait sea accumsan ut feugiat sadipscing amet stet. Elit eos vero.