Esta todo en $signed_request['page']['liked']
Código PHP:
Ver original<?php
$signed_request = $_REQUEST["signed_request"];
list($encoded_sig, $payload) = explode('.', $signed_request, 2); if(@$data['page']['liked'] == '1'){
echo '<script>location.href = "http://www.fan.com"</script>';
}else{
echo '<script>location.href = "http://www.nofan.com"</script>';
}
?>