(PHP 4 >= 4.0.2, PHP 5, PHP 7, PHP 8)
strncasecmp — Binary safe case-insensitive string comparison of the first n characters
This function is similar to strcasecmp(), with the difference that you can specify the (upper limit of the) number of characters from each string to be used in the comparison.
string1The first string.
string2The second string.
lengthThe length of strings to be used in the comparison.
   Returns a value less than 0 if string1
   is less than string2; a value greater
   than 0 if string1 is greater than
   string2, and 0 if they
   are equal.
   No particular meaning can be reliably inferred from the value aside
   from its sign.
  
| Version | Description | 
|---|---|
| 8.2.0 | This function is no longer guaranteed to return strlen($string1) - strlen($string2)when string lengths
  are not equal, but may now return-1or1instead. | 
Example #1 strncasecmp() example
<?php
$var1 = 'Hello John';
$var2 = 'hello Doe';
if (strncasecmp($var1, $var2, 5) === 0) {
    echo 'First 5 characters of $var1 and $var2 are equals in a case-insensitive string comparison';
}
?>
