[support] refreshing jcarousel item list without page reload

[Aldo Martinez Selleras]

I have this function callback

function classification( $a = NULL ) {
    global $base_url;
    $awards = profile_award('1');
    $n = count($awards);
    $items = array();
    for ( $x = 0; $x < $n; $x++) {
        array_push($items, "<img
src=\"$base_url/sites/default/files/viewer/objects/backgrounds/" .
$awards[$x]['background'] . "\" width=\"75\" height=\"75/>");
    }
    print drupal_json($items);
}

And when the select option change, it call this function:

function refresh_award() {
    $.get('/classification/', function(data){
     var node = JSON.decode(data);
     console.log( node ); // open firebug console to see the data
   });
};

But in firebug console I'm receiving this

JSON.decode is not a function
var node = JSON.decode(data);

why?