What is the DOM?

The browser's in-memory tree of your HTML

Back to Exercises

DOM Tree Preview

Click a button to highlight which DOM node is being referenced.

<html> ...
<body> ...
<header id="site-header">Site Header</header>
<main>Main Content</main>
// Selecting nodes const header = document.getElementById('site-header'); const main = document.querySelector('main'); const footers = document.getElementsByTagName('footer');

Full Code Used in This Demo

HTML

<header id="site-header">Site Header</header>
<main>Main Content</main>
<footer>Footer</footer>

CSS

.node { border: 1px solid #e2e8f0; border-radius: 8px; padding: 10px; }

JavaScript

function highlight(selector) {
  document.querySelectorAll('.node').forEach(n => n.classList.remove('highlight'));
  const el = document.querySelector(selector);
  if (el) el.classList.add('highlight');
}