$var1_a = "name";
$var1_b = "Richard";
$var2_a = "age";
$var2_b = "12";
$var3_a = "location";
$var3_b = "mars";

##</code><code>##

    $mech->submit_form(
        form_name => $search_form,
        fields      => {
            $forum_user     => $username,
            $forum_pass    => $password,
        }
    );