Written code is a strikingly poor representation of a running program. Consider this event listener: const thing = document.querySelector("#thing"); thing.addEventListener("click", () => { console.log("this is: ", this); }); Almost none of what we need to reason about this effectively is represented in the text of this little script: Nothing indicates how this should be run. Basic programming intuition tells us that we should run something that interprets this, but the process with browsers is f...