str_split function for multibytes

mb_str_split.php

<?php
function mb_str_split($str, $split_length) {
    $chars = array();
    $len = mb_strlen($str);
    for ($i = 0; $i < $len; $i+=$split_length ) {
        $chars[] = mb_substr($str, $i, $split_length); // only one char to go to the array
    }
    return $chars;
}

I passed $split_length as 6 for a string containing Arabic characters. It did't return the actual number of characters, rather it returned only 5 characters for $char[0] => sdبsd. Then I added 'UTF-8' parameter to mb_strlen() & mb_substr() and it worked like charm
Thank you :)

function mb_str_split($str, $split_length) {
    $chars = array();
    $len = mb_strlen($str, 'UTF-8'); 
    for ($i = 0; $i < $len; $i+=$split_length ) {
        $chars[] = mb_substr($str, $i, $split_length, 'UTF-8');
    }
    return $chars;
    }