Preventing Cross-Site Scripting (XSS) in Web Applications

Cross-Site Scripting (XSS) remains one of the most common and dangerous vulnerabilities in modern web development. Understanding how to block malicious scripts from executing in your users' browsers is essential for any developer building web applications.\n\nThis written course guides you from the fundamental concepts of web security to implementing robust, modern defense strategies. You will understand how XSS vulnerabilities occur and how to systematically eliminate them using industry-standard techniques.\n\nWhat you'll learn:\n- Understand the core types of XSS attacks, including stored, reflected, and DOM-based vulnerabilities\n- Implement robust input validation and context-aware output encoding to neutralize malicious payloads\n- Apply modern sanitization libraries and native browser APIs to handle user-generated HTML safely\n- Configure strong Content Security Policy (CSP) headers to restrict unauthorized script execution\n- Leverage modern web framework defenses and understand when they require manual security overrides\n\nYou will start by exploring essential security terminology and the mechanics of web browsers before progressing to practical code analysis and secure coding patterns. Through clear written explanations and structured HTML and JavaScript code snippets, you will learn how to audit and secure vulnerable application code.\n\nThis course is designed for beginner web developers, software engineers, and security enthusiasts who want to build a solid foundation in web application security. No prior security experience is required, though a basic understanding of HTML and JavaScript is helpful.\n\nRead through the modules to start writing secure, resilient web code today.