Cita:
Iniciado por Antc1993 
$.get('pagina.php', function(data){
var myPlayList = data;
});
variable local :)
fuera de esa función la variable no existe
Código HTML:
<html>
<head>
<title>Ejemplo</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">
$( function (){
var myPlayList = [
{name:"Tempered Song",mp3:"http://www.miaowmusic.com/mp3/Miaow-01-Tempered-song.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-01-Tempered-song.ogg"},
{name:"Hidden",mp3:"http://www.miaowmusic.com/mp3/Miaow-02-Hidden.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-02-Hidden.ogg"},
{name:"Lentement",mp3:"http://www.miaowmusic.com/mp3/Miaow-03-Lentement.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-03-Lentement.ogg"},
{name:"Lismore",mp3:"http://www.miaowmusic.com/mp3/Miaow-04-Lismore.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-04-Lismore.ogg"},
{name:"The Separation",mp3:"http://www.miaowmusic.com/mp3/Miaow-05-The-separation.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-05-The-separation.ogg"},
{name:"Beside Me",mp3:"http://www.miaowmusic.com/mp3/Miaow-06-Beside-me.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-06-Beside-me.ogg"},
{name:"Bubble",mp3:"http://www.miaowmusic.com/mp3/Miaow-07-Bubble.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-07-Bubble.ogg"},
{name:"Stirring of a Fool",mp3:"http://www.miaowmusic.com/mp3/Miaow-08-Stirring-of-a-fool.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-08-Stirring-of-a-fool.ogg"},
{name:"Partir",mp3:"http://www.miaowmusic.com/mp3/Miaow-09-Partir.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-09-Partir.ogg"},
{name:"Thin Ice",mp3:"http://www.miaowmusic.com/mp3/Miaow-10-Thin-ice.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-10-Thin-ice.ogg"}
];
$('a:last').click( function (){
$.getJSON('json.txt',
function(lista) {
myPlayList = lista;
$('#tamano').html('Ahora debe tener 2 pistas');
});
});
$('a:first').click( function (){
$('#tamano').html('Pistas: '+myPlayList.length);
});
});
</script>
</head>
<body>
<a href="#">Ver tamaño</a><br /><br />
<a href="#">Llamar lista</a><br /><br />
<div id="tamano"></div>
</body>
</html> el archivo json.txt
Código HTML:
[
{name:"Tempered Song",mp3:"http://www.miaowmusic.com/mp3/Miaow-01-Tempered-song.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-01-Tempered-song.ogg"},
{name:"Thin Ice",mp3:"http://www.miaowmusic.com/mp3/Miaow-10-Thin-ice.mp3",ogg:"http://www.miaowmusic.com/ogg/Miaow-10-Thin-ice.ogg"}
]