Just to confirm, is using:
$_SERVER["DOCUMENT_ROOT"]
the same as using: /
in HTML.
Eg. If current document is:
folder/folder/folder/index.php
I could use (in HTML) to start at the roort:
/somedoc.html
and to do the same in PHP I would have to use:
$_SERVER["DOCUMENT_ROOT"] . "/somedoc.html";
Is that correct? Is there an easier way to do it?
Yes, $_SERVER['DOCUMENT_ROOT'] contains the server side path which correlates to the client side URL path /. But, No they are not interchangeable.
They are not interchangeable because, for example, the server side path should never be sent to the client (HTML) side. The value of $_SERVER['DOCUMENT_ROOT'] is not /; it is the server's local file path to what the server shows the client at /. So, the value of ${$_SERVER['DOCUMENT_ROOT']}/images/thumbnail.png" may be the string /var/www/html/images/thumbnail.png on a server where it's local file at that path can be reached from the client side at the url http://example.com/images/thumbnail.png
note: $_SERVER['DOCUMENT_ROOT'] does not include a trailing /