(PHP 4 >= 4.3.0, PHP 5)
mb_substr_count — Count the number of substring occurrences
Counts the number of times the needle substring occurs in the haystack string .
The number of times the needle substring occurs in the haystack string .
Example #1 mb_substr_count() example
<?php
echo mb_substr_count("This is a test", "is"); // prints out 2
?>