What is the prototype represents in the following JavaScript code snippet?
function f() {};
Function f
A custom constructor
Prototype of a function
Not valid
Correct Answer :
B. A custom constructor
Explanation: All object instances have a constructor property that point to the constructor function that created it. A custom constructor is a constructor which requires no arguments and is created automatically by the compiler at the time of object creation if not created by the user.
Related Questions
A function with no return value is called ___________
Procedures
Method
Static function
Dynamic function
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
What happens in the following javaScript code snippet?
var count = 0;
while (count < 10)
{
console.log(count);
count++;
}
while (count < 10)
{
console.log(count);
count++;
}
The values of count are logged or stored in a particular location or storage
The value of count from 0 to 9 is displayed in the console
An error is displayed
An exception is thrown
Which of the following is not considered as an error in JavaScript?
Syntax error
Missing of semicolons
Division by zero
Missing of Bracket
What is the observation made in the following JavaScript code?
if (!a[i]) continue;
Skips the defined elements
Skips the existent elements
Skips the null elements
Skips the defined & existent elements
A conditional expression is also called a _______________
Alternative to if-else
Immediate if
If-then-else statement
Switch statement
Which of the operator is used to test if a particular property exists or not?
in
exist
within
exists
The enumeration order becomes implementation dependent and non-interoperable if ___________
If the object inherits enumerable properties
The object does not have the properties present in the integer array indices
The delete keyword is never used
Object.defineProperty() is not used
The escape sequence stands for _________
Floating numbers
Representation of functions that returns a value
is not present in JavaScript
Form feed
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++;
}
{
document.writeln(num);
}
while(num>=1)
{
document.writeln(num);
num++;
}
Code 1
Code 2
Both Code 1 and Code 2
Cannot Compare
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?
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
Consider the following code snippet
function f(o)
{
if (o === undefined) debugger;
}
What could be the task of the statement debugger?
{
if (o === undefined) debugger;
}
It does nothing but a simple breakpoint
It debugs the error in that statement and restarts the statements execution
It is used as a keyword that debugs the entire program at once
It is used to find error in the statement
One of the special feature of an interpreter in reference with the for loop is that ___________
Before each iteration, the interpreter evaluates the variable expression and assigns the name of the property
The iterations can be infinite when an interpreter is used
The body of the loop is executed only once
the iteration is finite when an interpreter is used
The snippet that has to be used to check if a is not equal to null is _________
if(a!=null)
if (!a)
if(a!null)
if(a!==null)
What happens in the following javaScript code snippet?
var count = 0;
while (count < 10)
{
console.log(count);
count++;
}
while (count < 10)
{
console.log(count);
count++;
}
The values of count are logged or stored in a particular location or storage
The value of count from 0 to 9 is displayed in the console
An error is displayed
An exception is thrown
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
What will be the output of the following JavaScript code?
1.01
1.047
1.00
1.4
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 happen if the body of a for/in loop deletes a property that has not yet been enumerated?
The property will be stored in a cache
The loop will not run
That property will not be enumerated
The property will be enumerated
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
The property of a primary expression is ____________
stand-alone expressions
basic expressions containing all necessary functions
contains variable references alone
contains only keywords
The reduce and reduceRight methods follow a common operation called __________
filter and fold
inject and fold
finger and fold
fold
The basic purpose of the toLocaleString() is to _________
return a localised object representation
return a parsed string
return a local time in the string format
return a localized string representation of the object
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 values=[1,2,3,4]
var ans=values.slice(1);
document.writeln(ans);
var ans=values.slice(1);
document.writeln(ans);
1, 2, 3, 4
2, 3, 4
1, 3, 4
error
JavaScript Code can be called by using ____________
RMI
Triggering Event
Preprocessor
Function/Method
Consider the following code snippet
function f(o)
{
if (o === undefined) debugger;
}
What could be the task of the statement debugger?
{
if (o === undefined) debugger;
}
It does nothing but a simple breakpoint
It debugs the error in that statement and restarts the statements execution
It is used as a keyword that debugs the entire program at once
It is used to find error in the statement
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);
var result;
switch(grade)
{
case 'A':
result+=10;
case 'B':
result+= 9;
case 'C':
result+= 8;
default:
result+= 0;
}
document.write(result);
10
0
18
17
What will be the output of the following Javascript code?
int a=0;
for(a;a<5;a++);
console.log(a);
for(a;a<5;a++);
console.log(a);
0
error
4
5