<?php

function get_string_between($string = '', $start, $end) {
    $startPos = strpos($string, $start);
    if ($startPos === false)
    {
        unset($string, $start, $end, $startPos);
        return '';
    }
    $string = substr($string, (strlen($start) + $startPos));
    unset($start, $startPos);
    $endPos = strpos($string, $end);
    if ($endPos === false)
    {
        unset($string, $end, $endPos);
        return '';
    }
    unset($end);
    $string = substr($string, -(strlen($string) + $endPos), $endPos);
    unset($endPos);
    return $string;
    unset($string);
}

$text = '<test>Lorem Ipsum</test>';
$text_between = get_string_between($text, '<test>', '</test>');

echo $text_between; // Lorem Ipsum

?>