As corion says, LWP::UserAgent does not use a browser at all. The code itself acts like a browser, doing the low level communication to a web server. I checked the LWP::UserAgent man page, and 'visible' is not one of the options to the constructor. I didn't expect it to be, either, since there is nothing but Perl code running when you use the module.

Why do you need to see a browser to process the response?