What are some best practices for handling special characters in PHP scripts?

Special characters in PHP scripts can cause issues such as syntax errors or unexpected behavior. To handle special characters properly, it's best to use functions like htmlspecialchars() to encode special characters before outputting them to the browser. This helps prevent XSS attacks and ensures that the characters are displayed correctly.

$string = "<script>alert('Hello, world!');</script>";
echo htmlspecialchars($string, ENT_QUOTES, 'UTF-8');