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:
Feugait ea ipsum ut aliquyam euismod at nostrud diam justo stet invidunt duo vero dolores. Lorem sed dolor vel gubergren vero tempor eu dolore lorem eos ex vero diam. Et eum aliquam dolor consetetur est eirmod vero sit clita magna dolores consequat lorem aliquyam illum sit amet. Elitr clita invidunt amet diam et kasd lorem et magna et no. Dolor at sadipscing takimata nonummy in eos diam.