It does not display a form field to fill in the code, regardless of if JavaScripts are enabled or disabled. (But, I figured out how to access it anyways, without much difficulty. So, the fact that the web page is not working is not much of a problem, really.)

(The web pages for displaying the existing explanations does work, though.)

Interesting. I can’t reproduce. Is it consistent across browsers? Can you try turning off Adblock?