i want to play song on router via wan interface. using help from exec() to play specific song is OK. but i want to play all exist song, so i use PHP to generate song list. but my problem is PHP don't receive message that i send by echo "<a href='song.php?play=song.mp3)'>"; when i detect for variable $play by
if(!$play)
{
    echo "error";
}
my script print error at browser
so what's wrong with my script