【3】.数组定义：
var myArray = [1,5,68,3];
OR：
var myArray = new Array();
OR：
var myArray = new Array(4);
OR：
var myArray = new Array(1,5,"Thomas", true);
OR：
var cities = new Array(4);
cities["Australia"] =
["Sydney", "Melbourne", "Canberra", "Perth", "Brisbane"];
cities["France"] =
["Paris", "Lyons", "Nice", "Dijon"];
cities["Japan"] = ["Tokyo", "Kyoto", "Osaka", "Nara"];
cities["New Zealand"] =
["Auckland", "Wellington", "Christchurch", "Dunedin", "Queenstown"];