Unit
- Client-Server Model: The web operates on a client-server architecture where browsers (clients) request resources from remote servers. Servers process requests and return responses, typically in HTML, CSS, JavaScript, or data formats like JSON. Understanding this request-response cycle is foundational to all web development work.
- HTTP Protocol: Hypertext Transfer Protocol governs communication between clients and servers. Key concepts include HTTP methods (
GET,POST,PUT,DELETE), status codes (200, 404, 500), and headers that carry metadata. Statelessness means each request is independent; session management is added through tokens or cookies. - Front-End vs. Back-End: Front-end refers to everything users see and interact with directly in the browser. Back-end includes server logic, databases, and APIs that power the front-end. Full-stack development combines both, requiring knowledge of how data flows between layers.
- Role of HTML: HTML provides the structure of web pages using elements like headings, paragraphs, links, images, and forms. Semantic HTML5 tags (
<header>,<nav>,<article>) improve accessibility and search engine optimization. - Role of CSS: CSS controls the visual presentation of HTML elements, including layout, colors, fonts, and animations. Modern CSS features like Flexbox and Grid enable responsive designs that adapt to different screen sizes.
- Role of JavaScript: JavaScript adds interactivity and dynamic behavior to web pages. It can manipulate the DOM, handle user events, fetch data asynchronously, and control client-side logic. Together with HTML and CSS, it forms the essential trio of front-end development.
- Web Browsers and Rendering: Browsers parse HTML and CSS to construct the Document Object Model (DOM) and CSS Object Model (CSSOM), then combine them into a render tree. Understanding the critical rendering path helps developers optimize page load performance.
- Development Tools: Browser developer tools (DevTools) allow inspection of elements, debugging JavaScript, analyzing network requests, and monitoring performance. Text editors and IDEs like VS Code provide syntax highlighting, linting, and version control integration.
- Version Control with Git: Git tracks changes to code over time, enabling collaboration and rollback. Platforms like GitHub host remote repositories, facilitate code reviews, and integrate with deployment pipelines. Commits, branches, and merges are fundamental workflows.
- Domain Name System (DNS): DNS translates human-readable domain names like example.com into IP addresses that servers use to locate resources. When you enter a URL, DNS resolution occurs before any HTTP request. Understanding DNS is crucial for configuring web hosting, email services, and troubleshooting network issues.
- Web Hosting and Deployment: Web hosting services store website files and make them accessible via the internet. Options include shared hosting, virtual private servers, and cloud platforms like AWS or Netlify. Deployment involves transferring code from development to production, often using continuous integration pipelines.
- Security Fundamentals: Web security protects data and users from threats like XSS, CSRF, and SQL injection. HTTPS encrypts data in transit using TLS certificates. Security best practices include input validation, authentication, authorization, and regular dependency updates.
- RESTful APIs: Representational State Transfer (REST) is a common architectural style for building APIs that allow front-end applications to interact with back-end services. REST uses standard HTTP methods and returns data in JSON or XML. Understanding endpoints, request/response structure, and status codes is essential.
Governance Requirement
Requirement: W3C Web Standards Compliance
The World Wide Web Consortium (W3C) publishes standards for HTML, CSS, and accessibility (WCAG). Adhering to these standards ensures cross-browser compatibility, long-term maintainability, and inclusive access for users with disabilities. Modern web applications must validate markup against W3C schemas and follow semantic practices to meet compliance requirements in regulated industries.
Quick Revision
- The client-server model and HTTP protocol form the foundation of web communication.
- HTML structures content, CSS styles it, and JavaScript adds behavior.
- Browser rendering involves DOM and CSSOM construction and the critical rendering path.
- Version control with Git is essential for collaborative development.
- W3C standards guide best practices for compatibility and accessibility.