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SSC MTS - JavaScript 1000+ MCQ [Solved] PDF Download

Thursday 9th of March 2023

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Downlaod JavaScript MCQ PDF
1. JavaScript is a _______________ language.
A. Object-Oriented
B. High-level
C. Assembly-language
D. Object-Based
Answer : D
2. What is the prototype represents in the following JavaScript code snippet?
function f() {};
A. Function f
B. A custom constructor
C. Prototype of a function
D. Not valid
Answer : B
3. Which of the following Attribute is used to include External JS code inside your HTML Document?
A. src
B. ext
C. script
D. link
Answer : A
4. What will be the output of the following JavaScript code?
int sum=0;
var arr = [10,15,20,30];
arr.forEach(function myFunction(element)
{
sum= sum+element;
});
document.writeln(sum);
A. 70
B. 75
C. 10
D. error
Answer : B
5. JavaScript _________ when there is an indefinite or an infinite value during an arithmetic computation.
A. Prints an exception error
B. Prints an overflow error
C. Displays Infinity
D. Prints the value as such
Answer : C
6. What will be the output of the following JavaScript code?
function output(option)
{
return (option ? yes : no);
}
bool ans=true;
console.log(output(ans));
A. Yes
B. No
C. Runtime error
D. Compilation error
Answer : A
7. Assume that we have to convert false that is a non-string to string. The command that we use is (without invoking the new operator).
A. false.toString()
B. String(false)
C. String newvariable=false
D. Both false.toString() and String(false)
Answer : D
8. What is a block statement in JavaScript?
A. conditional block
B. block that contains a single statement
C. both conditional block and a single statement
D. block that combines multiple statements into a single compound statement
Answer : D
9. Consider the following code snippet.
while (a != 0)
{
if (a == 1)
continue;
else
a++;
}

What will be the role of the continue keyword in the above code snippet?
A. The continue keyword restarts the loop
B. The continue keyword skips the next iteration
C. The continue keyword skips the rest of the statements in that iteration
D. The continue keyword breaks out of the loop
Answer : C
10. Consider the following code snippet.
while (a != 0)
{
if (a == 1)
continue;
else
a++;
}

What will be the role of the continue keyword in the above code snippet?
A. The continue keyword restarts the loop
B. The continue keyword skips the next iteration
C. The continue keyword skips the rest of the statements in that iteration
D. The continue keyword breaks out of the loop
Answer : C
11. JavaScript Code can be called by using ___________
A. RMI
B. Triggering Event
C. Preprocessor
D. Function/Method
Answer : D
12. The primary purpose of the array map() function is that it __________
A. maps the elements of another array into itself
B. passes each element of the array and returns the necessary mapped elements
C. passes each element of the array on which it is invoked to the function you specify, and returns an array containing the values returned by that function
D. pass the elements of the array into another array
Answer : C
13. What will be the output of the following Javascript code?
var a = 10;
do {
a += 1;
console.log(a);
} while (a < 5);
A. 11121314
B. 1112
C. 12345
D. 11
Answer : D
14. The reduce and reduceRight methods follow a common operation called __________
A. filter and fold
B. inject and fold
C. finger and fold
D. fold
Answer : B
15. What will happen if a return statement does not have an associated expression?
A. It returns the value 0
B. It will throw an exception
C. It returns the undefined value
D. It will throw an error
Answer : C
16. The main purpose of a Live Wire in NetScape is to ________
A. Create linkage between client side and server side
B. Permit server side, JavaScript code, to connect to RDBMS
C. Support only non relational database
D. To interpret JavaScript code
Answer : B
17. A function definition expression can be called as __________
A. Function prototype
B. Function literal
C. Function calling
D. Function declaration
Answer : B
18. The statement a===b refers to _________
A. Both a and b are equal in value, type and reference address
B. Both a and b are equal in value
C. Both a and b are equal in value and type
D. There is no such statement
Answer : C
19. What will be the output of the following Javascript code?
var a= 0;
var b = 0;
while (a < 3)
{
a++;
b += a;
console.log(b);
}
A. 135
B. 123
C. 013
D. 01
Answer : A
20. What will be the output of the following JavaScript code?
var grade='E';
var result;
switch(grade)
{
case 'A':
result+=10;
case 'B':
result+= 9;
case 'C':
result+= 8;
default:
result+= 0;
}
document.write(result);
A. 10
B. 0
C. 18
D. 17
Answer : B
21. The purpose of extensible attribute is to __________
A. make all of the own properties of that object non configurable
B. to configure and bring a writable property
C. lock down objects into a known state and prevent outside tampering
D. to include new properties into the object
Answer : C
22. What will happen if reverse() and join() methods are used simultaneously?
A. Reverses and stores in the same array
B. Reverses and concatenates the elements of the array
C. Reverses
D. Stores the elements of an array in normal order
Answer : A
23. What is the observation made in the following JavaScript code?
if (!a[i]) continue;
A. Skips the defined elements
B. Skips the existent elements
C. Skips the null elements
D. Skips the defined & existent elements
Answer : C
24. What will be the output of the following JavaScript code?
function equalto()
{
int num=10;
if(num===10)
return true;
else
return false;
}
A. true
B. false
C. runtime error
D. compilation error
Answer : A
25. Which is a more efficient JavaScript code snippet?
Code 1 :
for(var num=10;num>=1;num--)
{
document.writeln(num);
}

Code 2 :
var num=10;
while(num>=1)
{
document.writeln(num);
num++;
}
A. Code 1
B. Code 2
C. Both Code 1 and Code 2
D. Cannot Compare
Answer : A
26. What will be the output of the following JavaScript code?
function compare()
{
int a=1;
char b=1;
if(a.tostring()===b)
return true;
else
return false;
}
A. true
B. false
C. runtime error
D. logical error
Answer : A
27. A proper scripting language is a __________
A. High level programming language
B. Assembly level programming language
C. Machine level programming language
D. Low level programming language
Answer : A
28. The pop() method of the array does which of the following task?
A. decrements the total length by 1
B. increments the total length by 1
C. prints the first element but no effect on the length
D. updates the element
Answer : A
29. A function with no return value is called ___________
A. Procedures
B. Method
C. Static function
D. Dynamic function
Answer : A
30. The generalised syntax for a real number representation is __________
A. [digits][.digits][(E|e)[(+|-)]digits]
B. [digits][+digits][(E|e)[(+|-)]digits]
C. [digits][(E|e)[(+|-)]digits]
D. [.digits][digits][(E|e)[(+|-)]digits]
Answer : A
31. The unordered collection of properties, each of which has a name and a value is called _________
A. String
B. Object
C. Serialized Object
D. Array
Answer : B
32. What will be the output of the following JavaScript code?
function output(object)
{
var place=object ? object.place : Italy;
return clean:+ place;
}
console.log(output({place:India}));
A. clean:India
B. clean:Italy
C. error
D. undefined
Answer : A
33. What will be the possible output of the following JavaScript code?
var a = [1,2,3,4,5];
a.slice(0,3);
A. Returns [1,2,3]
B. Returns [4,5]
C. Returns [1,2,3,4]
D. Returns [1,2,3,4,5]
Answer : C
34. The method or operator used to identify the array is __________
A. isarrayType()
B. ==
C. ===
D. typeof
Answer : D
35. What will be the output of the following JavaScript code?
var grade='B';
var result;
switch(grade)
{
case 'A':
{
result+=10;
break;
}
case 'B':
{
result+= 9;
break;
}
case 'C':
{
result+= 8;
break;
}
default:
result+= 0;
}
document.write(result);
A. 10
B. 9
C. 8
D. 0
Answer : B
36. What will be the output of the following JavaScript code?
const obj = {prop: 12};
Object.preventExtensions(obj);
console.log( Object.isExtensible(obj));
A. 12
B. false
C. true
D. error
Answer : B
37. Consider the following code snippet :
var c = counter(), d = counter();
c.count()
d.count()
c.reset()
c.count()
d.count()

The state stored in d is :
A. 1
B. 0
C. Null
D. Undefined
Answer : A
38. The type of a variable that is volatile is _______________
A. Volatile variable
B. Mutable variable
C. Immutable variable
D. Dynamic variable
Answer : B
39. JavaScript is ideal to ________
A. make computations in HTML simpler
B. minimize storage requirements on the web server
C. increase the download time for the client
D. increase the loading time of the website
Answer : B
40. What will be the step of the interpreter in a jump statement when an exception is thrown?
A. The interpreter stops its work
B. The interpreter throws another exception
C. The interpreter jumps to the nearest enclosing exception handler
D. The interpreter throws an error
Answer : C
41. What will be the output of the following Javascript code?
<script>
txt1 = “ one”;
txt1 += “two”;
document.getElementById("demo").innerHTML = txt1;
</script>
A. onetwo
B. one two
C. error
D. undefined
Answer : A
42. What is the observation made in the following JavaScript code?
var count = [1,,3];
A. The omitted value takes undefined
B. This results in an error
C. This results in an exception
D. The omitted value takes an integer value
Answer : A
43. What will be the output of the following JavaScript code?
var grade='A';
var result;
switch(grade)
{
case 'A':
result+=10;
case 'B':
result+= 9;
case 'C':
result+= 8;
default:
result+= 0;
}
document.write(result);
A. 10
B. 27
C. 8
D. 0
Answer : B
44. An expression that can legally appear on the left side of an assignment expression. is a well known explanation for variables, properties of objects, and elements of arrays. They are called ___________
A. Properties
B. Prototypes
C. Lvalue
D. Definition
Answer : C
45. What will be the equivalent code of the following JavaScript code?
o.m(x,y);
A. o.m(x) && o.m(y);
B. o[m](x,y);
C. o(m)[x,y];
D. o.m(x && y);
Answer : B
46. Consider the following code snippet
function f(o)
{
if (o === undefined) debugger;
}

What could be the task of the statement debugger?
A. It does nothing but a simple breakpoint
B. It debugs the error in that statement and restarts the statements execution
C. It is used as a keyword that debugs the entire program at once
D. It is used to find error in the statement
Answer : A
47. What will be the output of the following Javascript code?
int size=5;
int a=5;
int size=4;
for(int j=size;j>=0;j--)
{
console.log(a);
a=a-2;
}
A. 5555
B. 5321
C. 531-1
D. 531
Answer : C
48. What will be the output of the following Javascript code?
<script>
document.getElementById("demo").innerHTML = typeof "John"
</script>
A. integer
B. number
C. string
D. error
Answer : C
49. When does the function name become optional in JavaScript?
A. When the function is defined as a looping statement
B. When the function is defined as expressions
C. When the function is predefined
D. when the function is called
Answer : B
50. The one-liner code that concatenates all strings passed into a function is
A. 
function concatenate()
{
return String.prototype.concat('', arguments);
}

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

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

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

Answer : D
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