1、理解组数栈内存与栈内存的关系 2、引用类型在数组的使用
<script>
var a = 3,b;
b = a;
console.log(b,a);//结果为3，3
b = 4;
console.log(b,a);//结果为4，3
var arr = [1,2,3];
var arr1 = arr;
console.log(arr1,arr);//结果为[1,2,3]和[1,2,3]
arr1[0] = 4;
console.log(arr1,arr);//结果为[4,2,3]和[4,2,3]
arr[1] = 5;
console.log(arr1,arr)
var arr2 = arr1;
arr2.push("black");
console.log(arr,arr1,arr2);
var arr3 = [0,1];
console.log(arr,arr3);
</script>
