what does strtolower do in php code example

Example 1: strtolower php

strtolower ( string $string ) : string 
//Returns string with all alphabetic characters converted to lowercase.
$string = 'HELLO WORLD';
echo strtolower($string); //Output: 'hello world'
$string = 'HeLlO WoRlD';
echo strtolower($string); //Output: 'hello world'

Example 2: tolower php

The strtolower() function is used to convert a string into lowercase. This function takes a string as parameter and converts all the uppercase english alphabets present in the string to lowercase.