What Is the JavaScript Event Loop?

The Chinese version of this post is my translation of an English article, Altitude Labs' "What is the JavaScript Event Loop?"¹. Please read the original for the full walkthrough: it uses a few short code examples and step-by-step diagrams to show how the call stack, the event table, the event queue and the event loop cooperate when setTimeout schedules a callback.

What follows are only the parts I added myself.

A Different Analogy for the Call Stack

To explain the call stack, the original compares it to people getting in and out of an elevator. I didn't find that very vivid, so in my translation I replaced it with a human pyramid: the first person to climb on can only come down last, and the last person to climb on is the first to come down.

A Follow-Up Question

Question: is the delay you set in setTimeout exact?