Like this...I think:
<?php
$string = "This is a string with some characters in it. Feel free to use whatever length of string you want to use. It really doesn't matter because the code understands what you need to do.";
$array = explode("", $string);
$array_size = sizeof($array);
$num = 14;
while ($num<=$array_size) {
$replacement=$array[$num]."<br>";
array_splice($array, $num, 1, $replacement);
$num = $num+15;
}
$new_cool_string = implode("", $array);
?>
If it doesn't work, PM me.
