Escape output using htmlspecialchars() to prevent cross-site scripting (XSS) attacks

Cross-site scripting (XSS) attacks occur when untrusted data is displayed on a web page without proper sanitization. By using the htmlspecialchars() function, special characters in the output are converted to their HTML entities, preventing the browser from interpreting them as code. This helps protect against XSS vulnerabilities and ensures that user-supplied data is displayed safely.