What are the best practices for handling user input in PHP to prevent security vulnerabilities like XSS attacks?

To prevent security vulnerabilities like XSS attacks when handling user input in PHP, it is important to sanitize and validate the input data before using it in your application. This can be achieved by using functions like htmlspecialchars() to escape special characters and prevent script injection. Additionally, using prepared statements when interacting with a database can help prevent SQL injection attacks. 

// Sanitize user input to prevent XSS attacks
$user_input = htmlspecialchars($_POST['user_input']);

// Validate user input to ensure it meets certain criteria
if (strlen($user_input) < 50) {
    // Proceed with using the sanitized user input
    echo "User input: " . $user_input;
} else {
    // Handle validation error
    echo "Input is too long.";
}

Keywords

input validation htmlspecialchars filter_input htmlentities cross-site scripting

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