Are you asking how to make comments? It would help if we could see your codepen.
I’m guessing your JS is inside a
<script> element? If so remove the script tags.
<button> too to see what happens.Maybe I’ll try adding backticks too.
For the HTML you have to use HTML Entities for Reserved characters .
I assuming you are writing this… straight up into your
<script> document.getElementById( "hi" ).innerHTML = "doing something" </script>
You need to convert your angle bracket using entity code.
The result is here…