If you didn't want to potentially lock the browser, you could do it this way which just keeps chugging through songs until they are all processed.
function play_next(){
var song = data.songs.shift(); // Removes the first song and stores it in song
$('#nowartist').append('song starting');
$.get("http://localhost/play.php", function(ret_data){
alert('done');
if(data.songs.length) play_next(); // Call next song if more songs exist;
});
}
play_next(); // Start it off
Note, it does alter the data.songs
array by removing items upon processing. If this is a problem, duplicate the array before starting so it removes elements from the duplicate array.
On a side note, I am assuming you didn't paste all your code... right now it loads the same page for every song, but nothing from the song
item is being used to alter the request in any way.