Events and forms

React to clicks and typing, and validate a form before it goes anywhere.

12 min read · Lesson 5 of 6 · Pro

Events are things that happen

A click. A key press. A form submit. The page finishing load. Your code does not run in a straight line waiting for these. It registers a function and the browser calls it later.

JavaScript

const btn = document.querySelector("#save");

btn.addEventListener("click", function () {
  console.log("Button was clicked");
});

The second argument is a callback: a function you hand over for someone else to call. That idea appears everywhere in JavaScript.

Common event names: click, input, change, submit, keydown, mouseenter, DOMContentLoaded.

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