superblobals – php has built in superglobals variables that we can use to create a fully dynamic link. Superglobals are always available in all scopes

                $_SERVER[‘PHP_SELF’];       

          $_SERVER[‘SERVER_NAME’];

The above 2 superglobals are just a couple of examples of the built in variables, we can use to help us build a dynamic link. If you are using them in a form to get information from the user, you will need to run some security checks.