JavaScript MCQ Questions with answers and solutions Page 5

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Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. Consider the following code snippet :
The state stored in q is :

Code:

var p = counter(), q = counter(); 
p.count()
q.count() 
p.reset() 
p.count() 
q.count()

(A) Undefined
(B) Null
(C) 0
(D) 1

💬 Discuss

✅ Correct Answer: (D) 1

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Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. What is the difference between the two lines given below ?

Code:

!!(object1 && object2);
(object1 && object2);

(A) Both the lines checks just for the existence of the object alone
(B) The first line results in a real boolean value whereas the second line merely checks for the existence of the objects
(C) Both the lines result in a boolean value “False”
(D) Both the lines result in a boolean value “True”

💬 Discuss

✅ Correct Answer: (B) The first line results in a real boolean value whereas the second line merely checks for the existence of the objects

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Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. For the below mentioned code snippet:
The equivalent statement is

Code:

var obj = new Object();

(A) Object obj=new Object();
(B) var obj= new Object;
(C) var obj;
(D) var obj = Object();

💬 Discuss

✅ Correct Answer: (B) var obj= new Object;

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Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. If you have a function f and an object o, you can define a method named m of o with

(A) obj=fun.meth;
(B) obj=fun;
(C) obj.meth=meth.fun;
(D) obj.meth=fun;

💬 Discuss

✅ Correct Answer: (D) obj.meth=fun;

V

Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. The one-liner code that concatenates all strings passed into a function is

(A) function concatenate() { return String.concat.apply('', arguments); }
(B) function concatenate() { return String.prototype.concat('', arguments); }
(C) function concatenate() { return String.prototype.concat.apply('', arguments); }
(D) function concatenate() { return String.prototype.apply('', arguments); }

💬 Discuss

✅ Correct Answer: (A) function concatenate() { return String.concat.apply('', arguments); }

V

Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. Consider the following code snippet :

Code:

var string2Number=parseInt("456pqr");

(A) 456pqr
(B) Exception
(C) NaN
(D) 456

💬 Discuss

✅ Correct Answer: (D) 456

V

Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. Consider the following code snippet : will this code work?

Code:

var tensquared = (function(n) {return n*n;}(100));

(A) Exception will be thrown
(B) Memory leak
(C) Error
(D) Yes

💬 Discuss

✅ Correct Answer: (D) Yes

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Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. Do functions in JavaScript necessarily return a value?

(A) some functions do not return any value
(B) It is mandatory
(C) Not necessary
(D) Few functions return values by default

💬 Discuss

✅ Correct Answer: (D) Few functions return values by default

V

Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. Consider the following code snippet :

Code:

var Total=eval("5*5+10");

(A) 35 as an integer value
(B) 35 as a string
(C) Exception is thrown
(D) 5*5+10

💬 Discuss

✅ Correct Answer: (A) 35 as an integer value

V

Vishal Gupta

🎓 Tutor III ⭐ 7.73K Points

📊 JavaScript

Q. Consider the following code snippet.
Which is an equivalent code for the above code snippet?

Code:

opt.fun(p,q);

(A) opt.fun(p && q);
(B) opt(fun)["p","q"];
(C) opt.fun(p) && opt.fun(q);
(D) opt["fun"](p,q);

💬 Discuss

✅ Correct Answer: (D) opt["fun"](p,q);

JavaScript MCQs with answers Page - 5

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