In what ways can the output context changes in the HTML output be managed to prevent XSS vulnerabilities in the PHP code?

To prevent XSS vulnerabilities in PHP code, it is essential to properly manage the output context changes in the HTML output. This can be achieved by sanitizing user input, escaping output data, and using secure coding practices. By ensuring that all user-generated content is properly filtered and encoded before being displayed on the webpage, you can significantly reduce the risk of XSS attacks.

// Example of escaping output data to prevent XSS vulnerabilities
$user_input = "<script>alert('XSS attack!');</script>";
$escaped_output = htmlspecialchars($user_input, ENT_QUOTES, 'UTF-8');
echo $escaped_output;