將字串的字母全部轉為 小寫 並返回該字串。
strtolower ( st ring $string ) : string
Example:
$test1 = "APPLE and banana";
print_r(strtolower($test1));
$test2 = "2. APPLE and Banana";
print_r(strtolower($test2));
$test3 = 123;
print_r(strtolower($test3));
Output:
// strtolower($test1):
apple and banana
// strtolower($test2):
2. apple and banana
// strtolower($test3):
123