What are some best practices for handling user input in PHP to prevent Cross-Site Scripting (XSS) attacks?

Cross-Site Scripting (XSS) attacks occur when user input is not properly sanitized before being displayed on a webpage, allowing malicious scripts to be executed in the browser. To prevent XSS attacks in PHP, it is important to always sanitize and validate user input before displaying it on a webpage. This can be done by using functions like htmlspecialchars() to encode special characters and prevent script execution. 

// Sanitize user input to prevent XSS attacks
$user_input = "<script>alert('XSS attack!');</script>";
$sanitized_input = htmlspecialchars($user_input, ENT_QUOTES, 'UTF-8');

// Display sanitized input on the webpage
echo $sanitized_input;

Keywords

htmlspecialchars filter_input htmlentities strip_tags input validation

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