What's the fastest way to get all the ids into a single Javascript array?

json.json

{
  "id": "0",
  "item": [
    {
      "id": "1161736030",
      "open": "1",
      "text": "12\/14\/2013",
      "item": [
        {
          "id": "1163797134",
          "text": "CASE",
          "item": [
            {
              "id": "1",
              "text": "1214-1"
            }
          ]
        },
        {
          "id": "1163945744",
          "text": "HAHA",
          "item": [
            {
              "id": "2",
              "text": "1214-2"
            }
          ]
        }
      ]
    }
  ]
}

not sure about performence, but this works,

// test.js

var jsonString = '{"id":"0", "item":[{ "id":"1161736030",  "open":"1",  "text":"12/14/2013", "item":[{ "id":"1163797134",  "text":"CASE", "item":[{ "id":"1",  "text":"1214-1"}]},{ "id":"1163945744",  "text":"HAHA", "item":[{ "id":"2",  "text":"1214-2"}]}]}]}';

var json = JSON.parse(jsonString);

var ids_array = [];

function get_ids(node, ids_array){
  ids_array.push(node.id);

  if(node.item != undefined){
    for (var i = node.item.length - 1; i >= 0; i--) {
      var child = node.item[i]
      get_ids(child, ids_array);
    };
  }
}

get_ids(json, ids_array);

console.log(ids_array);

terminal output

node test.js                                                         
[ '0', '1161736030', '1163945744', '2', '1163797134', '1' ]