PHP: count amount of tabs at the beginning of a string

Ok basically I have a string which could be anything but for the purposes of the question it is:

    Hello World 

As you can see it has been indented twice at the beginning and once at the end. Is there a way to count the amount of tabs \t only at the开发者_运维百科 beginning of the string with PHP?

Cheers Franky

---

Try this code, it does exactly what you ask:

strspn($string, "\t");

http://www.php.net/strspn