Javascript Online Test

Time Left : 00 : 30 : 00

Which is true about JSON namespacing?

JSON namespaces can be accessed immediately after receiving data.
JSON namespaces can be accessed after parsing data.
JSON doesn't have namespaces. Though every object is inherently a namespace.

Correct Answer : C

Which of the following function of Array object applies a function simultaneously against two values of the array (from right-to-left) as to reduce it to a single value?

pop()
reduce()
push()
reduceRight()

Correct Answer : D

What keywords are reserved in JSON and cannot be used as keys?

Value
Object
There are none
Key

Correct Answer : C

The _______ method of an Array object adds and/or removes elements from an array

Reverse
Shift
Slice
Splice

Correct Answer : D

A linkage of series of prototype objects is called as :

prototype stack
prototype chain
prototype class
prototypes

Correct Answer : B

How do we define the term Thread?

Device that controls input
Variable that controls movement
Controlled execution of applications
None of the above

Correct Answer : C

Which of the following function of Array object adds one or more elements to the end of an array and returns the new length of the array?

pop()
push()
join()
map()

Correct Answer : B

Which method receives the return value of setInterval() to cancel future invocations?

clearInvocation()
cancelInvocation()
clearInterval()
clear()

Correct Answer : C

JavaScript Code can be called by using

RMI
Triggering Event
Preprocessor
Function/Method

Correct Answer : D

In this example, what is the TYPE of employee?

{ "employee" : { "type" : "Director", "functions" : ['sales', 'marketing'] } }

String
Array
Boolean
Object

Correct Answer : D

Which of the following are the errors in JavaScript?

Load time errors
Run time errors:
Logical Errors:
All of the above

Correct Answer : B

Which of the following is the correct syntax to redirect a url using JavaScript?

document.location='http://www.newUrl.com';
browser.location='http://www.newUrl.com';
navigator.location='http://www.newUrl.com';
window.location='http://www.newUrl.com';

Correct Answer : D

In this example, what is the VALUE of employee.type?

{ "employee" : { "type" : "Director", "functions" : ['sales', 'marketing'] } }

String
Object
Director

Correct Answer : C

Consider the following code snippet :

var book = {
“main title”: “JavaScript”,
‘sub-title’: “The Definitive Guide”,
“for”: “all audiences”,
author: {
firstname: “David”,
surname: “Flanagan”
}
};

In the above snippet, firstname and surname are

properties
property values
property names
objects

Correct Answer : C

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)

Correct Answer : D

Which of the following is a valid JSON string?

{ "meals" : { "breakfast" , "lunch" , "dinner" } }
{ "meals" : [ "breakfast" , "lunch" , "dinner" ] }
[ "meals" : { "breakfast" , "lunch" , "dinner" } ]
[ {"meals" : { "breakfast" , "lunch" , "dinner" } } ]

Correct Answer : B

The meaning for Augmenting classes is that:

objects inherit prototype properties even in dynamic state
objects inherit prototype properties only in dynamic state
objects inherit prototype properties in static state
object doesn’t inherit prototype properties in static state

Correct Answer : A

In this example, what would the VALUE of employee.functions[1] be?

{ "employee" : { "type" : "Director", "functions" : ['sales', 'marketing'] } }

null
undefined
marketing
sales

Correct Answer : C

A proper scripting language is a

High level programming language
Assembly level programming language
Machine level programming language
Low level programming language

Correct Answer : A

Among the keywords below, which one is not a statement?

if
with
debugger
use strict

Correct Answer : D

JavaScript is designed for following purpose -

to style HTML pages
to execute Queries related to databases on a server
to add interactivity to html pages
All of the above

Correct Answer : D

What is a closure?

Function objects
Scope where function’s variables are resolved
Both Function objects and Scope where function’s variables are resolved
Function return value

Correct Answer : C

What are the three important manipulations done in a for loop on a loop variable in javascript?

the initialization, the Incrementation, and update
the initialization, the test, and the update
the initialization, the test, and Incrementation
All of the above

Correct Answer : B

In what situation would you want to use XML over JSON?

When JSON is not offered.
When you need to use tags to structure your content.
You need message validation or you're using XSLT.
Never, JSON is worlds better.

Correct Answer : C

What is the output of following Javascript?

var a = 'java';
var b = 'script';
var c = a/b;
document.write(c);

javascript
java/script
NaN
None of the above

Correct Answer : C

What error does JSON.parse() throw when the string to parse is not valid JSON?

ReferenceError
EvalError
SyntaxError
TypeError

Correct Answer : C

What is used by the JSONObject and JSONArray constructors to parse JSON source strings?

JSONTokener
JSONParser
JParser
ParserJ

Correct Answer : A

What are the two basic groups of dataypes in JavaScript?

Primitive
Reference types
All of the above
None of the above

Correct Answer : C

True of False. The order of JSON objects is always preserved.

False
True

Correct Answer : A

Which statement about the replacer parameter in JSON.stringify() is true?

If null or omitted, all properties of the object are included in the resulting JSON string
If a function, transforms values and properties encountered while stringifying
All three statements are true
If an array, specifies the names of the properties in the object to include in the resulting JSON string

Correct Answer : C