Object.keys(
	obj1,    比较值 或 对象
    obj2     被比较值 或 对象
)

返回：Boolean  布尔




示例：
console.log(Object.is(10, 10));		//true
console.log(Object.is(10, 12));		//false
console.log(Object.is("abc", "abc"));	//true
console.log(Object.is(undefined, undefined));	//true
console.log(Object.is(undefined, null));	//false
console.log(Object.is(null, null));		//true
console.log(Object.is(NaN, NaN));		//true

var obj1 = {a:1,b:1};
var obj2 = {a:1,b:1};
console.log(Object.is(obj1.a, obj1.b));		//true
console.log(Object.is(obj1, obj2));			//false