An amazing JavaScript syntax feature-Basic Knowledge-js tutorial

JavaScript has many differences from the programming habits of C, Java, and so on, which may lead to many unexpected things. Today, we will discuss some javascript-related questions posted by zhihu about these tough syntax features, although it was a long time ago, these questions are quite classic, and javascript is really a tough language.

1.

The Code is as follows:

(Function (){
Return typeof arguments;
})();

A. "object"
B. "array"
C. "arguments"
D. "undefined"

Answer:

2.

The Code is as follows:

Var f = function g (){
Return 23;
};
Typeof g ();

A. "number"
B. "undefined"
C. "function"
D. Eorror

Answer: D

3.

The Code is as follows:

(Function (x ){
Delete x;
Return x;
}) (1 );

A. 1
B. null
C. undefined
D. Error

Answer:

4.

The Code is as follows:

Var y = 1,
X = y = typeof x;
X;

A. 1
B. "number"
C. undefined
D. "undefined"

Answer: D

5.

The Code is as follows:

(Function f (f ){
Return typeof f ();
}) (Function (){
Return 1;
});

A. "number"
B. "undefined"
C. "function"
D. Error

Answer:

6.

The Code is as follows:

Var foo = {
Bar: function (){
Return this. baz;
},
Baz: 1
};
(Function (){
Return typeof arguments [0] ();
}) (Foo. bar );

A. "undefined"
B. "object"
C. "number"
D. "function"

Answer:

7.

The Code is as follows:

Var foo = {
Bar: function (){
Return this. baz;
},
Baz: 1
};
Typeof (f = foo. bar )();

A. "undefined"
B. "object"
C. "number"
D. "function"

Answer:

8.

The Code is as follows:

Var f = (function f (){
Return "1 ";
}, Function g (){
Return 2;
})();
Typeof f;

A. "string"
B. "number"
C. "function"
D. "undefined"

Answer: B

9.

The Code is as follows:

Var x = 1;
If (function f (){}){
X + = typeof f;
}
X;

A. 1
B. "1 function"
C. "1 undefined"
D. NaN

Answer: C

10.

The Code is as follows:

Var x = [typeof x, typeof y] [1];
Typeof x;

A. "number"
B. "string"
C. "undefined"
D. "object"

Answer: B

11.

The Code is as follows:

(Function (foo ){
Return typeof foo. bar;
})({
Foo :{
Bar: 1
}
});

A. "undefined"
B. "object"
C. "number"
D. Error

Answer:

12.

The Code is as follows:

(Function f (){
Function f (){
Return 1;
}
Return f ();
Function f (){
Return 2;
}
})();

A, 1
B, 2
C. Error (e.g. "Too much recursion ")
D. undefined

Answer: B

13.

The Code is as follows:

Function f (){
Return f;
}
New f () instanceof f;

A, true
B. false

Answer: B

14.

The Code is as follows:

With (function (x, undefined) {}) length;

A, 1
B, 2
C. undefined
D. Error

Answer: B

15.

The Code is as follows:

Which of the following statements produces a running error :()
A. var obj = ();
B. var obj = [];
C. var obj = {};
D. var obj = //;

Answer: