get control name from any page that is on browserOf any site

Hi, Friends!

                  I want to get control or element name of a page of any web site on the browser. Means i want, when i open my asp.net web application then (http://www.facebook.com url is opend in it)i have a iframe or something like that in web application. Here is the point when is open then i want some value already in the text box of the facebook page.

i don't like to write value in it after opening i want value is already present in any text box on any page like facebook, gmail etc. I shall be very thankful to you for this kindness. Thanks a lot.