js 判断是数组还是对象

1.arr.constructor Array是数组 Object是对象

var arr=[];
console.log(arr.constructor==Array)   //true
console.log(arr.constructor==Object)   //false

2.arr instanceof Array 数组 true 对象 false

var arr={
     };
console.log(arr instanceof Array);   //false
console.log(arr instanceof Object);  //true

3.Object.prototype.toString.call([]) -->"[object Array]"
Object.prototype.toString.call({}) -->"[object Object]"

var arr=[];
var object={
     };
Object.prototype.toString.call(arr)  -->"[object Array]"
Object.prototype.toString.call(object)    -->"[object Object]"