curl乱码，求解


<?php
$host=$_GET['host'];
$searchmode=$_GET['ddlSearchMode'];
if(isset($_GET['host'])&&isset($_GET['ddlSearchMode']))
{
$ch=curl_init();
curl_setopt($ch,CURLOPT_URL,'http://whois.chinaz.com/reverse?host='.$host.'&ddlSearchMode='.$searchmode);
curl_setopt($ch,CURLOPT_HEADER,0);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); 
curl_setopt($ch,CURLOPT_USERAGENT,"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)"); 
curl_setopt($ch,CURLOPT_ENCODING ,'gzip');
$rs=curl_exec($ch);
//$rs = mb_convert_encoding($rs, "utf-8", "gb2312");
curl_close($ch);var_dump($rs);
?>