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

Web applications are constantly under threat, and Cross-Site Scripting (XSS) remains one of the most common and dangerous vulnerabilities on the client side. Understanding how malicious scripts are injected into trusted sites is the first step to building robust defenses. This text-only course guides you from security foundations to a practical understanding of web application defense. You will learn to analyze how vulnerabilities occur and apply modern secure coding practices to eliminate them entirely. What you'll learn: Understand the fundamental mechanics of Stored, Reflected, and DOM-based XSS attacks; Identify vulnerable data entry points in web forms, URLs, and client-side scripts; Apply robust input validation and context-aware output encoding to neutralize malicious payloads; Configure modern Content Security Policy (CSP) headers to restrict unauthorized script execution; Leverage built-in security features in modern front-end frameworks to prevent automatic rendering of unsafe HTML; Practice reviewing written code samples to spot hidden security flaws and implement reliable fixes. The course begins with essential security definitions and the basic anatomy of an injection attack, before moving step-by-step through practical defense strategies, modern browser security policies, and secure coding patterns. This program is designed for beginner web developers, QA engineers, and aspiring security analysts who have a basic grasp of HTML and JavaScript but no prior experience in web application security. Start reading today to secure your code and protect your users from client-side exploits.