How to Output 'Unknown' if id3.songname is missing?

programming flash
1

I tried to be as descriptive with the title as I could be,

Right now, I have my player setup to read the id3.songname and output into a dynamic textfield but how can I output a default message if an mp3 file is missing that info? Is there some type of if () statement I could use?

My code as is:

  
my_snd.onID3 = function(){
    for( var prop in my_snd.id3 ){
 info.track.text = my_snd.id3.songname;
    }
}

Thanks for any help at all on this one!

-Ind