What are some other documents that are a must-read?
You will want to learn the standard DOM methods. Walking the DOM as a tree structure as opposed to treating it as a database to query will increase your application capabilities. Learning to access the DOM without parsing a selector string will make your application many thousands of this new faster.
I suggest:
* https://gist.github.com/thegitfather/9c9f1a927cd57df14a59c26...
* https://prettydiff.com/2/guide/unrelated_dom.xhtml
* Web APIs - https://developer.mozilla.org/en-US/docs/Web/API
* RegExp - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guid...
* http - https://devhints.io/http-status
And then for more robust language/syntax support: https://rosettacode.org/wiki/Rosetta_Code
And for those who enjoy Vim but, like me, aren't masters quite yet. https://vim.rtorr.com/
I maintain my own guide of concise webdev tips that's mostly distill from and links to recommendations from OWASP, Mozilla and Google which you might find a good jumping-off point: https://www.checkbot.io/guide/