隐式创建 var arr=["Audi","BMW","Volvo"]; 直接实例化 var arr=new Array("Audi","BMW","Volvo"); 创建数组并给数组元素赋值 var arr=new Array(); arr[0]="Audi"; arr[1]="BMW"; arr[2]="Volvo";注意: console.log(arr.length); //3 arr[4]='jeep'; console.log(arr.length); //5 console.log(arr[3]); //undefined