What is a DOM tree and why is it needed?

DOM (Document Object Model) is an object model of a document that represents the structure of HTML or XML as a tree of nodes. Each element, attribute, and text in the document becomes a node in the tree.

The DOM tree is necessary for programs (such as browsers or server parsers) to dynamically access, modify, and manage the content and structure of a web page.

Example: in a browser, JavaScript can access the DOM tree to change text, add or remove elements, modify styles, etc.

// Changing the header text on the page
const header = document.getElementById('title');
header.textContent = 'New Header';

Thus, DOM is the link between the code and the visual representation of the document.