Web Security Fundamentals: Preventing Cross-Site Scripting (XSS)

Web applications are constantly under threat from vulnerabilities that allow attackers to inject malicious scripts into trusted websites. Understanding how Cross-Site Scripting (XSS) operates is the first and most critical step in securing your code and protecting your users. In this text-based course, you will transition from a web development beginner to a security-conscious developer capable of identifying, understanding, and mitigating XSS vulnerabilities. You will learn how attackers exploit weak input validation and how to implement robust, modern defenses to keep your applications safe. What you will learn: Understand the core mechanics of Stored, Reflected, and DOM-based XSS attacks; Analyze real-world historical security breaches to understand the impact of script injection; Implement secure coding practices including context-aware output encoding and input validation; Configure modern browser defense mechanisms like Content Security Policy (CSP); Leverage modern web framework protections and understand how to avoid common bypasses; Practice identifying vulnerable code blocks through guided written examples and exercises. The course begins with essential web security terminology, HTTP basics, and foundational definitions of script execution. From there, you will progress through detailed breakdowns of different attack vectors, real-world case studies, and hands-on secure coding strategies. This course is designed for beginner developers, QA testers, and aspiring security analysts who have a basic understanding of HTML and JavaScript but no prior background in web security. Start reading today to build a stronger, more secure foundation for your web development career.