一个关于json_decode()后显示为空的有关问题

一个关于json_decode()后显示为空的问题
代码如下，$data未转码之前还是正常的json格式数据，一转码直接变成Null了，求教大神帮忙看看是什么问题啊

header("Content-type:text/html;charset=utf-8");<br />$url = "http://218.22.201.163/wic/api.php/early_warning/xcyjservice/U/administrator/P/wic/jw/118.589036,30.055954";<br />       $postUrl = str_replace(' ', '%20', $url);<br />	   $param = '';<br />        $curlPost = $param;<br />        $ch = curl_init();<br />        curl_setopt($ch, CURLOPT_URL, $postUrl);<br />        curl_setopt($ch, CURLOPT_HEADER, 0);<br />        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);<br />        curl_setopt($ch, CURLOPT_POST, 1);<br />        curl_setopt($ch, CURLOPT_POSTFIELDS, $curlPost);<br />        curl_setopt($ch, CURLOPT_TIMEOUT, 60);<br />        $data = curl_exec($ch);<br />	<br />        curl_close($ch);<br />        //var_dump($data);die;//<br />        var_dump(json_decode($data, true));

------解决思路----------------------
你那个连接又 BOM 头！
json_decode(substr($data, 3), true)
就可以了