I've been trying to add web pages within a Canvas content page and have never been able to make it work. I only see a blank white page.
Here is the code I am using:
<iframe src="https://www.khanacademy.org/humanities/us-history/civil-war-era/sectional-tension-1850s/a/the-slave-economy" width="100%" height="700"></iframe>
I've tried http and https. I've tried other URLs (besides Khan). I've tried experimenting with the height and width fields. I've tested it in Chrome and Firefox. I've never seen anything but a blank white page.