Khan Academy has a button for sharing your CS project or program underneath the coding window.
Pressing the button works, but the resulting share link and code to embed your project on your own website sometimes cannot be copied.
This is a known error which occurs in Firefox. We apologize for the inconvenience.
Workaround: Switch browser. The functionality works in Chrome and may work in other browsers.
(Workaround initially published by a user here.)
Last updated: September 22nd, 2017