Custom HTML5 code editor not working

[alelordelo]

What I did
Copied the HTM5/JS/CSS from example bellow:
https://codepen.io/p5js/pen/wreBKy

Result
The HTML5 layer shows as empty:
https://gyazo.com/c151ae383b86d80b94935ce727f0cb21

Is there anything example on what that needs to be done to load HTM5/JS/CSS?

[alelordelo]

@salgum1114 , here is another example of HTM5/JS
https://drive.google.com/file/d/1hVA0M5NMV6BnY0WLSPPMmOUEr7SGErd1/view?usp=sharing

HTML opens fine when clicked:
https://gyazo.com/9c4effaa1963fe4c10dbdd5418218171

Then I copied HTM5/JS to the editor, but it doesn't show:
https://gyazo.com/201cad1a312f36dc5c035c35a9328d0e

Am I doing anything wrong?