On the collation of 14 Devil JS questions

1. (function () {

Return typeof arguments

})();

when returned here is the argument type, it is an array of classes, also on the object, so is object, exactly who is [object Argumens]

2

var f = function g () {

return 23;

};

typeof G ();

The problem is named function expression, but function name G only in the name scope valid, so the result is wrong, notice that the subject in the old IE is resolved to function declaration, that is, the result is number;

3

(function (x) {

Delete x;

return x;

}) (1);

Delete Deletes object properties, so this returns to 1;

4

var y = 1, x = y = typeof x;

X

It's obvious that undefined

5

(function f (f) {

Return typeof F ();

}) (function () {return 1;});

Number

6

var foo = {

Bar: function () {

return This.baz;

},

Baz:1

};

(function () {

Return typeof Arguments[0] ();

}) (Foo.bar);

Answer: undefined;

7

var foo = {

Bar:function () {

return This.baz;},

Baz:1}

typeof (F = foo.bar) ();

The subject is dead, the answer undefined, notice that the object only holds a reference to the method and does not hold the method

8

var f = (

function f () {

return "1";

},

function g () {

return 2;

}

)();

typeof F;

The answer is number;

9

var x = 1;if (function f () {}) {  x + = typeof F;} X
1undefined
10

var x = [typeof x, typeof y][1];typeof typeof X;
X is undefined
The type of x is a string;

11

(function (foo) {  return typeof Foo.bar;}) ({foo: {bar:1}});
It is obvious that undefined;
12

(function f () {  function f () {return 1;}  return f ();  function f () {return 2;}}) ();
The answer is 2, the variable promotion principle
13

function f () {return F;} New F () instanceof F;
False
14

With (function (x, undefined) {}) length;
Return when he arguments the length of the

On the collation of 14 Devil JS questions