采集程序登录成功~~可是COOKIES没有写入成文本

采集程序登录成功~~可是COOKIES没有写入成文本
cookes.txt   文件没有值
如何要把这次登录的COOKIES的值,提出来
<?php 
$cookie_jar = 'cookie.txt';
$data = array('mvfAdminMonths'   => '200706', 
              'mvfSiteProvinces' => 'Beijing', 
              'whichFirst'     => 'AS',
              '__act'        => '__id.22.SeatsQuery.adp.actList', 
  'submit.x'=> '28',
  'submit.y'=> '9'); 
$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL,'http://toefl.etest.edu.cn/cn/SeatsQuery'); 
curl_setopt($ch, CURLOPT_POSTFIELDS,$data); 
curl_setopt($ch, CURLOPT_RETURNTRANSFER,true); 
curl_setopt($ch, CURLOPT_COOKIEJAR, $cookie_jar);
//echo curl_exec($ch);
$contents= curl_exec($ch);//写入成文本 
  $file_name="dada.txt";        
        
        $handle = @fopen($save_path.$file_name,"w+"); 
        if ($handle) 
        { 
            if (@fwrite($handle,$contents)) 
            { 
                return  1; 
            }else 
            { 
                //写入文件错误 
                return -3;     
            } 
        }else 
        { 
            //文件不可写 
            return -4;     
        } 

?>