1arr.splice(index, 0, item);
2//explanation:
3inserts "item" at the specified "index",
4deleting 0 other items before it
1var arr = [];
2arr[0] = "Jani";
3arr[1] = "Hege";
4arr[2] = "Stale";
5arr[3] = "Kai Jim";
6arr[4] = "Borge";
7
8console.log(arr.join());
9arr.splice(2, 0, "Lene");
10console.log(arr.join());