I learned that it is possible to back reference capture groups and named capture groups in JavaScript regular expressions
Topic: JavaScript โ Page 14
A cheat sheet for JavaScript lookahead and lookbehind regular expressions.
HTML input elements hold references to their labels if there are any
The relatedTarget event property gives information about the previous/next element when dealing with focus events.
If the 2nd argument of String.prototype.replace is a string replacement patterns can create hard to find bugs