判断传入的参数是否是数组

var arr = [1,2,3];
var obj = {name:'zhangsan'}
console.log(Array.isArray(arr));
console.log(Array.isArray(obj));

function isArray(obj) {
return Object.prototype.toString.call(obj) === '[object Array]';
}
console.log(isArray(arr));
console.log(isArray(obj));

function isArr(obj) {
if (typeof obj === 'object') {
if (typeof obj.length === 'number') {
return 'Array';
} else {
return 'object';
}
}
}
console.log(isArr(arr));
console.log(isArr(obj));

function isArr(obj) {
return obj.constructor == Array;
}