Returns string with all alphabetic characters converted to uppercase.
Note that 'alphabetic' is determined by the current locale. For instance, in the default "C" locale characters such as umlaut-a (д) will not be converted.
$str = "Mary Had A Little Lamb and She LOVED It So";
$str = strtoupper($str);
echo $str; // Prints MARY HAD A LITTLE LAMB AND SHE LOVED IT SO