Explore topic-wise MCQs in Javascript.

This section includes 14 Mcqs, each offering curated multiple-choice questions to sharpen your Javascript knowledge and support exam preparation. Choose a topic below to get started.

1.

Consider the following code snippet :
function constfunctions() 
{
 var functions = [];
 for(var k = 0; k < 10; k++)
 functions [k] = function() { return k; };
 return functions ;
}
var functions = constfunctions();
functions [5]()

What does the last statement return ?

A. 10
B. 9
C. 0
D. All of above
E. None of these
Answer» B. 9
Discussion
2.

Consider the following code snippet :
var p = counter(), q = counter(); 
p.count()
q.count() 
p.reset() 
p.count() 
q.count()

The state stored in q is :

A. Undefined
B. Null
C. 0
D. 1
E. None of these
Answer» E. None of these
Discussion
3.

What is the difference between the two lines given below ?
!!(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
E. None of these
Answer» C. Both the lines result in a boolean value False
Discussion
4.

For the below mentioned code snippet:
var obj = new Object();

The equivalent statement is:

A. Object obj=new Object();
B. var obj= new Object;
C. var obj;
D. var obj = Object();
E. None of these
Answer» C. var obj;
Discussion
5.

Consider the following code snippet :
var string2Number=parseInt("456pqr");
A. 456pqr
B. Exception
C. NaN
D. 456
E. None of these
Answer» E. None of these
Discussion
6.

Consider the following code snippet :
var tensquared = (function(n) {return n*n;}(100));

Will the above code work ?

A. Memory leak
B. Exception will be thrown
C. Error
D. Yes
E. None of these
Answer» E. None of these
Discussion
7.

Consider the following code snippet :
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
E. None of these
Answer» B. 35 as a string
Discussion
8.

Consider the following code snippet
opt.fun(p,q);

Which is an equivalent code for the above code snippet?

A. opt.fun(p && q);
B. opt(fun)["p","q"];
C. opt.fun(p) && opt.fun(q);
D. opt["fun"](p,q);
E. None of these
Answer» E. None of these
Discussion
9.

Consider the following code snippet
function output(n) 
{
 for(var v in n)
 console.log(v + ": " + n[v] + " n");
}

What will the above code snippet result ?

A. prints only one property
B. Prints the contents of each property of n
C. prints the address of elements
D. Returns undefined
E. None of these
Answer» E. None of these
Discussion
10.

Consider the following code snippet
function hypotenuse(p, q) 
{
 function square(n) 
 { 
 return n*n; 
 }
 return Math.sqrt(square(p) + square(q));
}

What does the above code result?

A. Square of sum of p and q
B. Sum of p and q square
C. Sum of square of p and q
D. All of above
E. None of these
Answer» D. All of above
Discussion
11.

Which is an equivalent code to invoke a function fun of class opt that expects two arguments p and q?

A. opt.fun(p,q);
B. fun(p,q);
C. opt.fun(p) && opt.fun(q);
D. opt(p,q);
E. None of these
Answer» B. fun(p,q);
Discussion
12.

What is the difference between the two lines given below ?

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
E. None of these
Answer» C. Both the lines result in a boolean value False
Discussion
13.

Consider the following code snippet :

A. Undefined
B. Null
C. 0
D. 1
E. None of these
Answer» E. None of these
Discussion
14.

For the below mentioned code snippet:

A. Object obj=new Object();
B. var obj= new Object;
C. var obj;
D. var obj = Object();
E. None of these
Answer» C. var obj;
Discussion