How can XSS protection be implemented in a WYSIWYG editor for PHP applications?

XSS protection in a WYSIWYG editor for PHP applications can be implemented by sanitizing user input before displaying it on the page. This can be achieved by using functions like htmlspecialchars() or htmlentities() to escape special characters that could be used in XSS attacks.

// Sanitize user input before displaying in the WYSIWYG editor
$user_input = "<script>alert('XSS attack!');</script>";
$sanitized_input = htmlspecialchars($user_input);

// Display the sanitized input in the WYSIWYG editor
echo "<textarea>$sanitized_input</textarea>";