function updateOneFriend(friendID){
    var friendTag = $(friendID);
    var username = friendTag.readAttribute('username');
    var url = 'lastfm/getCurrentTrack.php?username='+encodeURIComponent(username);
    var successo = function(transport){
			var retObj = transport.responseText.evalJSON();
	    		if(retObj != null){
			    if(retObj.artist != "")
				friendTag.update(retObj.artist + ' - ' + retObj.track);
			    else
				friendTag.update('non in ascolto');
			}
		    };
    doQuery(url, successo);
}

function updateFriends(){
    var i = 0;
    var friendTag = null;
    while(true){
	friendTag = $("friend" +i);
	if(friendTag == null)
	    break;
	window.setTimeout('updateOneFriend("friend'+i+'")', i * 5000);
	++i;
    }

}