Get string between specified two strings

get_string_between.php

function get_string_between($string, $start, $end){
	$string = " ".$string;
	$ini = strpos($string,$start);
	if ($ini == 0) return "";
	$ini += strlen($start);   
	$len = strpos($string,$end,$ini) - $ini;
	return substr($string,$ini,$len);
}

$fullstring = "this is my [tag]dog[/tag]";
$parsed = get_string_between($fullstring, "[tag]", "[/tag]");

echo $parsed; // (result = dog)