wp_kses_check_attr_val( string $value, string $vless, string $checkname, mixed $checkvalue ): bool

1873function wp_kses_check_attr_val( $value, $vless, $checkname, $checkvalue ) {1874	$ok = true;1875 1876	switch ( strtolower( $checkname ) ) {1877		case 'maxlen':1878			/*1879			 * The maxlen check makes sure that the attribute value has a length not1880			 * greater than the given value. This can be used to avoid Buffer Overflows1881			 * in WWW clients and various Internet servers.1882			 */1883 1884			if ( strlen( $value ) > $checkvalue ) {1885				$ok = false;1886			}1887			break;1888 1889		case 'minlen':1890			/*1891			 * The minlen check makes sure that the attribute value has a length not1892			 * smaller than the given value.1893			 */1894 1895			if ( strlen( $value ) < $checkvalue ) {1896				$ok = false;1897			}1898			break;1899 1900		case 'maxval':1901			/*1902			 * The maxval check does two things: it checks that the attribute value is1903			 * an integer from 0 and up, without an excessive amount of zeroes or1904			 * whitespace (to avoid Buffer Overflows). It also checks that the attribute1905			 * value is not greater than the given value.1906			 * This check can be used to avoid Denial of Service attacks.1907			 */1908 1909			if ( ! preg_match( '/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value ) ) {1910				$ok = false;1911			}1912			if ( $value > $checkvalue ) {1913				$ok = false;1914			}1915			break;1916 1917		case 'minval':1918			/*1919			 * The minval check makes sure that the attribute value is a positive integer,1920			 * and that it is not smaller than the given value.1921			 */1922 1923			if ( ! preg_match( '/^\s{0,6}[0-9]{1,6}\s{0,6}$/', $value ) ) {1924				$ok = false;1925			}1926			if ( $value < $checkvalue ) {1927				$ok = false;1928			}1929			break;1930 1931		case 'valueless':1932			/*1933			 * The valueless check makes sure if the attribute has a value1934			 * (like `<a href="blah">`) or not (`<option selected>`). If the given value1935			 * is a "y" or a "Y", the attribute must not have a value.1936			 * If the given value is an "n" or an "N", the attribute must have a value.1937			 */1938 1939			if ( strtolower( $checkvalue ) !== $vless ) {1940				$ok = false;1941			}1942			break;1943 1944		case 'values':1945			/*1946			 * The values check is used when you want to make sure that the attribute1947			 * has one of the given values.1948			 */1949 1950			if ( ! in_array( strtolower( $value ), $checkvalue, true ) ) {1951				$ok = false;1952			}
When	Instructions	Calls it makes
always	11–26	`strtolower()`
always	15–30	`strtolower(), call_user_func()`
always	16–31	`strtolower(), strtolower()`
PHP	Compiled	Executed	Branches	Notes
8.6-dev	70	11–31	17
8.5	70	11–31	17
8.4	70	11–31	17	9 fewer instructions than PHP 8.3
8.3	79	11–34	17
8.2	79	11–34	17	1 more instruction than PHP 8.1
8.1	78	11–34	17
7.4	78	11–34	17