PHP采集这个网站是如何防采集的

$url='http://www.leisurelakesbikes.com/product/specializedtransitioncompracingbike2011.aspx?&id=16728';
$curl=curl_init($url);
curl_setopt($curl,CURLOPT_AUTOREFERER,1);
curl_setopt($curl,CURLOPT_RETURNTRANSFER,1);
$html=curl_exec($curl);
echo $html;

------解决方案--------------------
整个网页几乎都包含在一个hidden form里面，你留意一下，估计用了ajax和session