(PHP 4 >= 4.3.0, PHP 5, PHP 7) Make a string lowercase

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Return width of string

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Convert "kana" one from another ("zen-kaku", "han-kaku" and more)

(PHP 4 >= 4.4.3, PHP 5 >= 5.1.3, PHP 7) Check if the string is valid for the specified encoding

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Find position of first occurrence of string in a string

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Perform case folding on a string

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Encode character to HTML numeric string reference

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Regular expression match ignoring case with multibyte support

(PHP 5 >= 5.2.0, PHP 7) Finds the last occurrence of a character in a string within another

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Set start point of next regular expression match