UserAgent->get problem

Hi,all.
  I want to submit my request to a website, and I successfully parse the
"get" parameters.
   When I paste the url('http://mywebsite/search?aa=1&bb=2&JSEnable=true')
to firefox, it returns a successful value. However,
     $response=$ua->get($url);
   did not return the successful value.
Did any kind spirit help me figure it out?

  By the way,the website need username and password.I have use the
statements below to deal with it. And It seems work well, since I can
get the content of the webpages without problems.

my $response = $ua->post( $url,
    [  loginID=>$username,
    	 passwd => $passwd,
    ]
  );