XSS Prevention refers to techniques used to protect web applications from Cross-Site Scripting attacks, where malicious scripts are injected into trusted websites. To prevent these attacks, developers can implement measures such as input validation, which ensures that user inputs do not contain harmful code, and output encoding, which converts special characters into a safe format before displaying them on a webpage. Another effective strategy is the use of Content Security Policy (CSP), which allows web developers to specify which sources of content are trusted. By restricting the execution of scripts to only those from approved sources, CSP significantly reduces the risk of XSS vulnerabilities in web applications.