$data = array(
    'name' => 'Joe',
    'website' => 'www.phpstudy.net'
);
$data = http_build_query($data);
$data = json_encode($data);
$json = file_get_contents($url, 0, stream_context_create(array(
    'http' => array(
        'timeout' => 30,
        'method' => 'POST',
        'content' => $data
    )
)));