What are some best practices for ensuring proper encoding and handling of special characters in PHP scripts?

Special characters can cause issues when encoding and handling in PHP scripts, leading to potential security vulnerabilities or display problems. To ensure proper encoding and handling of special characters, it is recommended to use functions like htmlspecialchars() or htmlentities() to encode special characters before outputting them to the browser. Additionally, setting the correct character encoding in the HTML document and PHP script can help prevent encoding issues.

// Example of encoding special characters using htmlspecialchars()
$unsafe_string = "<script>alert('XSS attack');</script>";
$safe_string = htmlspecialchars($unsafe_string, ENT_QUOTES, 'UTF-8');
echo $safe_string;