Web Development Fundamentals

Clients, Servers, and the Internet The web is a conversation between clients and servers. Your browser is the client. It sends requests asking for resources, and servers respond ...

HTTP Is a Request and Response Protocol HTTP, the HyperText Transfer Protocol, defines how clients and servers exchange messages. A client sends a request line with a method, a ...

The Skeleton of an HTML Page HTML, the HyperText Markup Language, gives content its structure in the browser. A document opens with the doctype declaration telling the browser to ...

Selectors and Rules CSS, the Cascading Style Sheets language, controls presentation. A stylesheet is made of rules. Each rule has a selector that targets elements and a ...

Flexbox Lays Out One Dimension Flexbox is a layout mode for arranging items in a single row or column. You set display flex on a container, and its direct children become flexible ...

JavaScript Runs in the Browser JavaScript is the language of interactivity on the web. It can fetch data, validate forms, animate the page, and react to clicks. Browsers expose a ...

Design for Every Screen People browse on phones, tablets, laptops, and ultrawide monitors. Responsive design makes one set of HTML and CSS adapt to all of them. The classic ...

The Form Element Forms collect input from users. Every form has a method and an action. The action is the URL where the data goes, and the method is the HTTP verb, almost always ...

Applications Split into Frontend and Backend A modern web app is really two programs. The backend owns data and business rules and exposes an API, a set of endpoints that external ...

Why These Matter Accessibility means everyone can use your site, including people relying on screen readers, keyboards, or voice control. Performance means the site loads and ...