1var colors=["red","blue"];
2var index=1;
3
4//insert "white" at index 1
5colors.splice(index, 0, "white"); //colors = ["red", "white", "blue"]
6
1var arr1 = ["Hello"," "];
2var arr2 = ["World","!"];
3var both = arr1.concat(arr2);
4//both = ["Hello"," ","World","!"];