How to get the url as default value for a field of a webform

Hello,
I am using webform embedded in the profile page of each user. The webform has a field that I would like to show by default the url of the page where it is shown. I tried the %get[q] but I get as a result the user/uid , however this is not the url of the page as I am using pathauto , the url will be somenthing like users/username. How can I get to pass the username value to the field by default?
Please bear in mind that the form is filled in by anonimous users viewing the member profile so the username I want to get in the default field of the webform is the one of the member being viewed (which is also shown in the url).
Many thanks
Fabio