What is the purpose of using htmlentities in PHP when dealing with form input?

When dealing with form input in PHP, using htmlentities is important to prevent cross-site scripting (XSS) attacks. By converting special characters to HTML entities, it ensures that user input is displayed as plain text rather than being interpreted as code. This helps to protect your website from malicious scripts that could be injected through form submissions.

// Example of using htmlentities to sanitize form input
$user_input = $_POST['user_input'];
$sanitized_input = htmlentities($user_input);
echo "Sanitized input: " . $sanitized_input;