1.先定义再赋值
var myArray1 = new Array(); //不定义元素个数
myArray1[0] = "第";
myArray1[1] = "一";
myArray1[2] = "种";
var myArray2 = new Array(3); //定义元素的个数
myArray2[0] = "第";
myArray2[1] = "二";
myArray2[2] = "种";
2.定义数组时同时赋值
var myArray3 = new Array("第","三","种");
//你需要在数组内指定数值或者逻辑值,那么变量类型应该是数值变量或者布尔变量,而不是字符变量
var myArray4 = [
{"num":"1001","name":"jack","age":16},
{"num":"1002","name":"Mary","age":17},
{"num":"1003","name":"Tom","age":19}
];
//注意中括号和大括号的位置
3. 注意
· 数组只有数组长度一个属性
· 如果没有给数组赋值得到的是undefined,打印是”“
· 数组长度不够可以自动扩充,不存在越界的问题