To determine whether one object is the prototype of (or is part of the prototype chain of) another object, one should use the ____________
isPrototypeOf() method
equals() method
=== operator
==opertor
Correct Answer :
A. isPrototypeOf() method
Explanation: Prototype is a global property which is available with almost all the objects. To determine whether one object is the prototype of (or is part of the prototype chain of) another object, one should use the isPrototype() method. To find out if p is the prototype of o write p.isPrototypeOf(o).
Related Questions
What will be the output of the following JavaScript code?
const obj1 = { property1: '10'};
const obj2 = Object.freeze(obj1);
obj2.property1 = '20';
console.log(obj2.property1);
const obj2 = Object.freeze(obj1);
obj2.property1 = '20';
console.log(obj2.property1);
10
20
Runtime error
Compilation error
JavaScript _________ when there is an indefinite or an infinite value during an arithmetic computation.
Prints an exception error
Prints an overflow error
Displays Infinity
Prints the value as such
For the below mentioned code snippet:
var o = new Object();
The equivalent statement is:
var o = Object();
var o;
var o= new Object;
Object o=new Object();
In the following syntax, the data type within the square brackets must be ___________
book[datatype]=assignment_value;
An integer
A String
An object
Floating point
Consider the following JavaScript statements.
var text = testing: 1, 2, 3; // Sample text
var pattern = /d+/g // Matches all instances of one or more digits
In order to check if the pattern matches with the string text, the statement is ____________
var pattern = /d+/g // Matches all instances of one or more digits
text==pattern
text.equals(pattern)
text.test(pattern)
pattern.test(text)
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);
}
var b = 0;
while (a < 3)
{
a++;
b += a;
console.log(b);
}
135
123
013
01
Consider the following code snippet :
var grand_Total=eval(10*10+5);
The output for the above statement would be :
10*10+5
105 as a string
105 as an integer value
Exception is thrown
What will the following code snippet work? If not, what will be the error?
function tail(o)
{
for (; o.next; o = o.next) ;
return o;
}
{
for (; o.next; o = o.next) ;
return o;
}
No, this will throw an exception as only numerics can be used in a for loop
No, this will not iterate
Yes, this will work
No, this will result in a runtime error with the message Cannot use Linked List
Consider the following code snippet.
for(var p in o)
console.log(o[p]);
The above code is equivalent to which code?
console.log(o[p]);
for (var i = 0;i < a.length;i++)
console.log(a[i]);
for (int i = 0;i < a.length;i++)
console.log(a[i]);
for (var i = 0;i <= a.length;i++)
console.log(a[i]);
for (var i = 1;i < a.length;i++)
console.log(a[i]);
A proper scripting language is a __________
High level programming language
Assembly level programming language
Machine level programming language
Low level programming language
What will be the output of the following JavaScript code?
function compare()
{
int num=2;
char b=2;
if(a==b)
return true;
else
return false;
}
{
int num=2;
char b=2;
if(a==b)
return true;
else
return false;
}
true
false
runtime error
compilation error
What will be the output of the following JavaScript code?
Int a=1;
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
10
0
1
Undefined
What is a block statement in JavaScript?
conditional block
block that contains a single statement
both conditional block and a single statement
block that combines multiple statements into a single compound statement
What will be the output of the following Javascript code?
var a = 10;
do {
a += 1;
console.log(a);
} while (a < 5);
do {
a += 1;
console.log(a);
} while (a < 5);
11121314
1112
12345
11
What will be the step of the interpreter in a jump statement when an exception is thrown?
The interpreter stops its work
The interpreter throws another exception
The interpreter jumps to the nearest enclosing exception handler
The interpreter throws an error
What is the observation made in the following JavaScript code?
var count = [1,,3];
The omitted value takes undefined
This results in an error
This results in an exception
The omitted value takes an integer value
Which of the following Attribute is used to include External JS code inside your HTML Document?
src
ext
script
link
What will be the output of the following JavaScript code?
int a==2;
int b=4;
int ans=a+b;
print(ans);
int b=4;
int ans=a+b;
print(ans);
2
6
0
error
What will be the output of the following Javascript code?
var add=new Function(num1,num2,return num1+num2);
document.writeln(add(2,5));
document.writeln(add(2,5));
2
5
Error
7
What will be the output of the following JavaScript code?
var val1=[1,2,3];
var val2=[6,7,8];
var result=val1.concat(val2);
document.writeln(result);
var val2=[6,7,8];
var result=val1.concat(val2);
document.writeln(result);
1, 2, 3
Error
1, 2, 3, 6, 7, 8
123
What will be the output of the following JavaScript code?
var arr = [7, 5, 9, 1];
var value = Math.max.apply(null, arr);
document.writeln(value);
var value = Math.max.apply(null, arr);
document.writeln(value);
7
5
1
9
The pop() method of the array does which of the following task?
decrements the total length by 1
increments the total length by 1
prints the first element but no effect on the length
updates the element
The object has three object attributes namely ________
Class, parameters, objects extensible flag
Prototype, class, objects parameters
Prototype, class, objects extensible flag
Native object, Classes and Interfaces and Objects extensible flag
What will be the output of the following JavaScript code?
var a=5 , b=1
var obj = { a : 10 }
with(obj)
{
alert(b)
}
var obj = { a : 10 }
with(obj)
{
alert(b)
}
10
Error
1
5
The reduce and reduceRight methods follow a common operation called __________
filter and fold
inject and fold
finger and fold
fold
What will be the output of the following Javascript code?
function range(int length)
{
int a=5;
for(int i=0;i<length;i++)
{
console.log(a);
}
}
range(3);
{
int a=5;
for(int i=0;i<length;i++)
{
console.log(a);
}
}
range(3);
5
555
3
error
JavaScript can be written __________
directly into JS file and included into HTML
directly on the server page
directly into HTML pages
directly into the css file
What will be the output of the following JavaScript code?
string a = hi;
string b =there;
alert(a+b);
string b =there;
alert(a+b);
hi
there
hithere
undefined
What will be the output of the following JavaScript code?
Int a=1;
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
if(a>10)
{
document.write(10);
}
else
{
document.write(a);
}
10
0
1
Undefined
What will be the output of the following JavaScript code?
125
25
5
Error