What are the best practices for handling character encoding issues in PHP scripts?

Character encoding issues in PHP scripts can be handled by ensuring that all input and output data is consistently encoded in the same character set, typically UTF-8. Use functions like mb_convert_encoding() to convert strings to the desired encoding, and htmlentities() to encode special characters. Additionally, setting the default_charset directive in php.ini to UTF-8 can help prevent encoding issues.

// Set default character encoding to UTF-8
ini_set('default_charset', 'UTF-8');

// Convert input string to UTF-8 encoding
$input = mb_convert_encoding($input, 'UTF-8');

// Encode special characters in output string
$output = htmlentities($output, ENT_QUOTES, 'UTF-8');