DAY11-12 :1. What is the DOM, and how does the browser create it?

DOM (Document Object Model) is a tree-like representation of your web page.
It converts your HTML and XML documents into objects and nodes so JavaScript can read, modify, or delete elements dynamically.
Think of it as a live interface between your code and what you see in the browser.

When

The browser creates the DOM right after it downloads and parses the HTML file, before rendering the page fully.
It’s updated in real time when JavaScript manipulates elements (e.g., adding or removing nodes).

Where

The DOM exists inside the browser’s memory as part of its rendering engine (e.g., Blink for Chrome, Gecko for Firefox).
You interact with it through JavaScript in the browser environment (window.document).

How

Parse HTML → The browser reads raw HTML and tokenizes it.
Create Nodes → Each tag, attribute, and piece of text becomes a node.
Build Tree → Nodes are connected into a tree structure (the DOM tree).
Attach CSSOM → CSS is parsed into a CSS Object Model (CSSOM) and combined with the DOM for rendering.
Render → The browser paints the pixels on screen based on the DOM + CSSOM.

Example:
If you write:

<body>
  <h1>Hello</h1>
  <p>World</p>
</body>

The DOM tree looks like:

Document
 └─ html
    └─ body
       ├─ h1 ("Hello")
       └─ p ("World")

You can access the <h1> using JavaScript:

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