Here's what I can comment about your code:

$ur_1=$mech->get($ur_1);

Calling the get method returns an HTTP::Response object. You can call the methods it provides, but generally it's more convenient call the various "STATUS METHODS" found in the WWW::Mechanize documentation to make sure your GET request was successful.

To see the content of the page, print the return string from the content method to validate your page's output (my $html = $mech->content).

To do a POST, you simply use the post method found in LWP::UserAgent. Since it's the base class for WWW::Mechanize, any method found in LWP::UserAgent can be called by WWW::Mechanize (make sure to read the "overloaded methods" section in the documentation though.)