A linkage of series of prototype objects is called as ________
prototype stack
prototype chain
prototype class
prototypes
Correct Answer :
B. prototype chain
Explanation: Consider an example, Date.prototype inherits properties from Object.prototype, so a Date object created by new Date() inherits properties from both Date.prototype and Object.prototype. This linked series of prototype objects is known as prototype chain.
Related Questions
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
If you have a function f and an object o, you can define a method named m of o with
o.m=m.f;
o.m=f;
o=f.m;
o=f;
The method or operator used to identify the array is __________
isarrayType()
==
===
typeof
A proper scripting language is a __________
High level programming language
Assembly level programming language
Machine level programming language
Low level programming language
Which attribute is used to specify that the script is executed when the page has finished parsing? (only for external scripts)
parse
a sync
defer
type
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
The script tag must be placed in __________
the head tag
the head or body
the title or head
after the body tag
The function definitions in JavaScript begins with _____________
Identifier and Parentheses
Return type and Identifier
Return type, Function keyword, Identifier and Parentheses
Identifier and Return type
What will be the output of the following JavaScript code?
const object1 = {};
a = Symbol('a');
b = Symbol.for('b');
object1[a] = 'harry';
object1[b] = 'derry';
const objectSymbols = Object.getOwnPropertySymbols(object1);
console.log(objectSymbols.length);
a = Symbol('a');
b = Symbol.for('b');
object1[a] = 'harry';
object1[b] = 'derry';
const objectSymbols = Object.getOwnPropertySymbols(object1);
console.log(objectSymbols.length);
0
2
1
Error
Consider the following code snippet.
function printArray(a)
{
var len = a.length, i = 0;
if (len == 0)
console.log(Empty Array);
else
{
do
{
console.log(a[i]);
} while (++i < len);
}
}
What does the above code result?
{
var len = a.length, i = 0;
if (len == 0)
console.log(Empty Array);
else
{
do
{
console.log(a[i]);
} while (++i < len);
}
}
Prints the numbers in the array in order
Prints the numbers in the array in the reverse order
Prints 0 to the length of the array
Prints Empty Array
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 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 is ideal to ________
make computations in HTML simpler
minimize storage requirements on the web server
increase the download time for the client
increase the loading time of the website
What will be the output of the following JavaScript code?
var a1 = [,,,];
var a2 = new Array(3);
0 in a1
0 in a2
var a2 = new Array(3);
0 in a1
0 in a2
true false
false true
true true
false true
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
Do functions in JavaScript necessarily return a value?
It is mandatory
Not necessary
Few functions return values by default
some functions do not return any value
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
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]);
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
What will be the output of the following JavaScript code?
function output(option)
{
return (option ? yes : no);
}
bool ans=true;
console.log(output(ans));
{
return (option ? yes : no);
}
bool ans=true;
console.log(output(ans));
Yes
No
Runtime error
Compilation error
The web development environment (JavaScript) offers which standard construct for data validation of the input entered by the user.
Controlled loop constructs
Case checking constructs
Validation constructs
All of the mentioned
Consider the following code snippet :
var tensquared = (function(x) {return x*x;}(10));
Will the above code work ?
Yes, perfectly
Error
Exception will be thrown
Memory leak
The var and function are __________
Keywords
Declaration statements
Data types
Prototypes
The reduce and reduceRight methods follow a common operation called __________
filter and fold
inject and fold
finger and fold
fold
In the following switch syntax, the expression is compared with the case labels using which of the following operator(s)?
switch(expression)
{
statements
}
{
statements
}
==
equals
equal
===
The purpose of extensible attribute is to __________
make all of the own properties of that object non configurable
to configure and bring a writable property
lock down objects into a known state and prevent outside tampering
to include new properties into the object
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)
The unordered collection of properties, each of which has a name and a value is called _________
String
Object
Serialized Object
Array
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
What will be the output of the following JavaScript code?
1.01
1.047
1.00
1.4