Alternative to $_SERVER['document_root'] as a relative argument
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I'm using [PHP File Tree][1] to build a directory for a site, and I'm curious what alternatives I have to `$_SERVER['DOCUMENT_ROOT']` to make the argument I'm passing through to a function become relative.

The page that calls the function is within the directory I am using the function on, so normally `$_SERVER['DOCUMENT_ROOT']` would be perfect except my virtual host is using that directory as the root directory for a domain name.  

So, for example, my server/hosting address is `http://s389593949.servername.com` but the domain `www.heresmysite.com` resolves to `http://s389593949.servername.com/HERESMYSITE/`, so the document root when used in the function returns `www.heresmysite.com/HERESMYSITE/therealfile.file` when it should be `www.heresmysite.com/therealfile.file`.  

Is there something I can put in place of `$_SERVER['DOCUMENT_ROOT']` to make it relative?  Something like `"/"` or `"../HERESMYSITE/"` so when the file name and link are appended they are correct to the relative path?  Those do not work.

(Yes, I am aware I can modify the PHP of the function itself, but I'm hoping to leave that untouched as I wish to use it in the future for other applications)

Many thanks, SO.


  [1]: http://www.abeautifulsite.net/blog/2007/06/php-file-tree/