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. All other numeric characters or special characters in the string remains unchanged.
Syntax:
string strtolower( $string )
Parameter: The only parameter to this function is a string that is to be converted to lower case.
Return value: This function returns a string in which all the alphabets are lower case.
Examples:
Input : $str = "GeeksForGeeks"
strtolower($str)
Output: neveropen
Input : $str = "going BACK he SAW THIS 123$#%"
strtolower($str)
Output: going back he saw this 123$#%
Below programs illustrate the strtolower() function in PHP:
Program 1:
<?php   // original string $str = "GeeksForGeeks";   // string converted to lower case $resStr = strtolower($str);   print_r($resStr);   ?> |
Output:
neveropen
Program 2:
<?php   // original string $str = "going BACK he SAW THIS 123$#%";   // string converted to lower case $resStr = strtolower($str);   print_r($resStr);   ?> |
Output:
going back he saw this 123$#%
Reference:
http://php.net/manual/en/function.strtolower.php
PHP is a server-side scripting language designed specifically for web development. You can learn PHP from the ground up by following this PHP Tutorial and PHP Examples.
