What are some best practices for securing a PHP application against cross site scripting (XSS) attacks?

Cross-site scripting (XSS) attacks occur when an attacker injects malicious scripts into web pages viewed by other users. To prevent XSS attacks in PHP applications, it is essential to properly sanitize and validate user input before displaying it on the website. 

// Sanitize and validate user input using htmlspecialchars function
$user_input = htmlspecialchars($_POST['user_input'], ENT_QUOTES, 'UTF-8');

// Display the sanitized input on the website
echo $user_input;

Keywords

htmlspecialchars htmlentities Content Security Policy filter_input XSS defense

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