function post($url,$data=array())
{
if ( !empty($data) )
{
$data=http_build_query($data);
}

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_TIMEOUT,2);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // 当设置为0时$ch没有返回值，直接输出请求的内容
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
curl_setopt($ch, CURLOPT_HEADER, 0);
$output = curl_exec($ch);
curl_close($ch);
return $output;
}