Introduction to HTML & How the Web Works

HyperText Markup Language (HTML) is the ubiquitous foundation of the World Wide Web. Every website you visit—from simple documentation hubs to intricate single-page web applications—is structured with HTML.

1. The Client-Server Web Lifecycle

When you enter a URL like https://devifyblog.com in your browser: 1. DNS Resolution: The browser queries DNS servers to resolve the domain name into an IP address. 2. HTTP / TLS Handshake: A secure connection is established using TCP and TLS. 3. HTTP GET Request: The browser asks the web server for the index HTML file. 4. HTML Parsing & DOM Construction: The browser reads the incoming byte stream, converts it into tokens, builds nodes, and constructs the Document Object Model (DOM). 5. Render Tree & Paint: Styles (CSS) and interactivity (JavaScript) are attached, resulting in visual pixels on your display.

2. What is a Markup Language?

Unlike programming languages like Python or C# that execute algorithms, a markup language uses tags to annotate text, declaring how content should be structured:

<p>This is a paragraph of text explaining web concepts.</p>

• <p>: Opening tag.
• This is a paragraph...: Inner text content.
• </p>: Closing tag with a forward slash.
• The combination of tags and content is an HTML Element.

3. The Evolutionary Timeline of HTML

• HTML 1.0 (1991): Created by Tim Berners-Lee at CERN with basic text anchors.
• HTML 4.01 (1999): W3C standard introducing tables, forms, and stylesheets.
• XHTML (2000): Strict XML-compliant HTML requiring closed tags and lowercase syntax.
• HTML5 (2014 - Present): Modern living standard introducing native audio/video, canvas, semantic tags, and rich web APIs.