The problem with this displaying on a wallboard is that it's using ' to escape apostrophes in its gadget html. The wallboard escapes and unescapes apostrophes using :
Fiddling around with the debug console, I was able to edit the escape sequence for the apostrophe and the wallboard worked, but I don't think there's any reliable way to get these to work without the source code itself being modified to be compatible.
Here's a workaround gist that you can install with Greasemonkey or Tampermonkey:
https://gist.github.com/nikki-lesl/54745d747c89e242b571e237ac04d16a