R4RIN – MCQs, Mock Tests | JavaScript Javascript MCQ Questions Set 1

Which of the following is not JavaScript Data Types?

1. Undefined
2. Number
3. Boolean
4. Float

✅ Correct Answer: 4

Which company developed JavaScript?

1. Netscape
2. Bell Labs
3. Sun Microsystems
4. IBM

✅ Correct Answer: 1

Inside which HTML element do we put the JavaScript?

1. <script>
2. <head>
3. <meta>
4. <style>

✅ Correct Answer: 1

Which of the following is correct about features of JavaScript?

1. It can not Handling dates and time.
2. JavaScript is a object-based scripting language.
3. JavaScript is not interpreter based scripting language.
4. All of the above

✅ Correct Answer: 2

Choose the correct JavaScript syntax to change the content of the following HTML code.

1. document.getElement ("letsfindcourse").innerHTML = "I am a letsfindcourse";
2. document.getElementById ("letsfindcourse").innerHTML = "I am a letsfindcourse";
3. document.getId ("letsfindcourse") = "I am a letsfindcourse";
4. document.getElementById ("letsfindcourse").innerHTML = I am a letsfindcourse;

✅ Correct Answer: 2

which of the following are advantages of JavaScript?

1. Less server interaction
2. Increased interactivity
3. Richer interfaces
4. All of the above

✅ Correct Answer: 4

Which of the following true about Javascript?

1. A. Client-side JavaScript does not allow the reading or writing of files
2. JavaScript cannot be used for networking applications
3. JavaScript doesn't have any multi-threading or multiprocessor capabilities
4. All of the above

✅ Correct Answer: 4

Microsoft has developed a popular HTML editor called?

1. Dreamweaver
2. FrontPage
3. HomeSite
4. Macromedia

✅ Correct Answer: 2

HomeSite 5 is a well-liked HTML and JavaScript editor from Macromedia.

1. True
2. False
3. Can be true or false
4. Can not say

✅ Correct Answer: 1

JavaScript ignores?

1. spaces
2. tabs
3. newlines
4. All of the above

✅ Correct Answer: 4

JavaScript is designed for following purpose -

1. to style HTML pages
2. to execute Queries related to databases on a server
3. to add interactivity to html pages
4. All of the above

✅ Correct Answer: 4

What will be the output of the following Javascript code? var string1 = "Letsfindcourse"; var intvalue = 30; alert( string1 + intvalue );

1. Letsfindcourse 30
2. 30
3. Letsfindcourse30
4. Exception

✅ Correct Answer: 3

Among the following, which one is a ternary operator in JavaScript? A.

1. #
2. ::
3. &:
4. ?:

✅ Correct Answer: 4

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

1. the initialization, the Incrementation, and update
2. the initialization, the test, and the update
3. the initialization, the test, and Incrementation
4. All of the above

✅ Correct Answer: 2

What does javascript use instead of == and !=?

1. It uses bitwise checking
2. It uses === and !== instead
3. It uses equals() and notequals() instead
4. It uses equalto()

✅ Correct Answer: 2

What should appear at the very end of your JavaScript? The <script language="javascript"> tag

1. <script>
2. <script>
3. </script language="javascript">
4. All of the above

✅ Correct Answer: 2

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

1. if
2. with
3. debugger
4. use strict

✅ Correct Answer: 4

How do we define the term Thread?

1. Device that controls input
2. Variable that controls movement
3. Controlled execution of applications
4. None of the above

✅ Correct Answer: 3

Which symbol is used for comments in Javascript?

1. \
2. //
3. * *
4. * */

✅ Correct Answer: 2

What are the types of Pop up boxes available in JavaScript?

1. Alert
2. Prompt
3. Confirm
4. All of the above

✅ Correct Answer: 4

what is the disadvantage of using innerHTML in JavaScript?

1. Content can not be replaced everywhere
2. We can use like "appending to innerHTML
3. Even if you use +=like "innerHTML = innerHTML + 'html'" still the old content is replaced by html
4. The entire innerHTML content is not re-parsed and build into elements, therefore its not slower

✅ Correct Answer: 3

What are the two basic groups of dataypes in JavaScript?

1. Primitive
2. Reference types.
3. All of the above
4. None of the above

✅ Correct Answer: 3

Which of the following are the functional components in JavaScript?

1. First-class functions
2. Encapsulated-class functions
3. Fixed-class functions
4. All of the above

✅ Correct Answer: 1

Which of the following is not the properties of screen objects in JavaScript?

1. AvailHeight
2. ColorsDepth
3. AvailWidth
4. ColorDepth

✅ Correct Answer: 2

Find output of below code var a = '20'; var b = a = 30; document.write(a+b);

1. Error in Script
2. '20'30
3. 2030
4. 50

✅ Correct Answer: 4

What is divide by 0 in Javascript? var a = 10; var b = 0; document.write(a/b);

1. Nothing is printed
2. 0 is printed
3. Infinity is printed
4. Some Garbage Value

✅ Correct Answer: 3

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?

1. pop()
2. reduce()
3. push()
4. reduceRight()

✅ Correct Answer: 4

What is the output of following Javascript? var a = 'letsfind'; var b = 'course'; var c = a/b; document.write(c);

1. letsfindcourse
2. letsfind/course
3. NaN
4. None of the above

✅ Correct Answer: 3

How ++ works in Javascript? Find output of below Javascript code. var a = 1; document.write(a--); document.write(a);

1. 00
2. 01
3. 11
4. 10

✅ Correct Answer: 4

Find output of below Javascript addition code document.write("1 plus 1 is " + 1 + 1);

1. 2
2. 1 plus 1 is 2
3. 1 plus 1 is 11
4. 1 plus 1 is 1 + 1

✅ Correct Answer: 3

Does JavaScript allow exception handling?

1. Yes, it provides try, catch as well as throw key word for exception handling
2. Yes, but it provides only try block
3. Yes, but it provides only Try catch block, but does not allow throw exception
4. No

✅ Correct Answer: 1

Which of the following method checks if its argument is not a number?

1. isNaN()
2. nonNaN()
3. NaN()
4. None of the above

✅ Correct Answer: 1

What if you use parseInt() to convert a string containing decimal value?

1. Throws Error
2. It returns the decimal values in string form
3. If returns only the integer portion of the number
4. None of the listed option

✅ Correct Answer: 3

What if you use parseInt() to convert a string containing decimal value?

1. Throws Error
2. It returns the decimal values in string form
3. If returns only the integer portion of the number
4. None of the listed option

✅ Correct Answer: 3

What is the output of below Javascript code? alert (typeof new Date() );

1. Throws Error
2. object
3. Displays Nothing
4. Current Date

✅ Correct Answer: 2

What if we put ++ operator inside if condition? find the output of below code < script> var a = 10; if(a == a++) document.write(a);

1. Error
2. Nothing is printed
3. 10
4. 11

✅ Correct Answer: 4

Which of the following is true?

1. If onKeyDown returns false, the key-press event is cancelled.
2. If onKeyPress returns false, the key-down event is cancelled.
3. If onKeyDown returns false, the key-up event is cancelled.
4. If onKeyPress returns false, the key-up event is canceled.

✅ Correct Answer: 1

Syntax for creating a RegExp object: 1. var txt=new RegExp(pattern,attributes); 2. var txt=/pattern/attributes; Which of the above mentioned syntax will correct?

1. 1 only
2. 2 only
3. Both 1 and 2
4. None of the above

✅ Correct Answer: 3

If para1 is the DOM object for a paragraph, what is the correct syntax to change the text within the paragraph?

1. para1="New Text"
2. para1.value="New Text";
3. para1.firstChild.nodeValue= "New Text";
4. para1.nodeValue="New Text";

✅ Correct Answer: 2

The syntax of Eval is ________________

1. [objectName.]eval(numeric)
2. [objectName.]eval(string)
3. [EvalName.]eval(string)
4. [EvalName.]eval(numeric)

✅ Correct Answer: 2

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

1. Reverse
2. Shift
3. Slice
4. Splice

✅ Correct Answer: 4

Which tag(s) can handle mouse events in Netscape?

1. <IMG>
2. <A>
3. <BR>
4. <span>

✅ Correct Answer: 1

Consider the following code snippet const pi=3.14; var pi=4; console.log(pi); What will be the output for the above code snippet?

1. This will flash an error
2. Prints 4
3. Prints 3.14
4. Ambiguity

✅ Correct Answer: 1

What is the default value of the asyc attribute?

1. 0
2. 1
3. False
4. True

✅ Correct Answer: 4

What is the purpose of the Attr object in the HTML DOM?

1. Used to focus on a particular part of the HTML page
2. HTML Attribute
3. Used to arrange elements
4. None of the mentioned

✅ Correct Answer: 2

What is the purpose of the Attr object in the HTML DOM?

1. A. Used to focus on a particular part of the HTML page
2. HTML Attribute
3. Used to arrange elements
4. None of the mentioned

✅ Correct Answer: 2

Which among the following POSIX signals generate events?

1. SIGDOWN
2. SIGFLOAT
3. SIGINT
4. SIGSHORT

✅ Correct Answer: 3

Javascript is ideal to?

1. make computations in HTML simpler
2. minimize storage requirements on the web server
3. increase the download time for the client
4. None of the mentioned

✅ Correct Answer: 2

The meaning for Augmenting classes is that:

1. objects inherit prototype properties even in dynamic state
2. objects inherit prototype properties only in dynamic state
3. objects inherit prototype properties in static state
4. object doesn’t inherit prototype properties in static state

✅ Correct Answer: 1

Which is the handler method used to invoke when uncaught JavaScript exceptions occur?

1. Onhalt
2. Onerror
3. Both onhalt and onerror
4. Onsuspend

✅ Correct Answer: 2

Consider the code snippet given below var count = [1,,3]; What is the observation made?

1. The omitted value takes "undefined"
2. This results in an error
3. This results in an exception
4. The omitted value takes an integer value

✅ Correct Answer: 1

What does the interpreter do when you reference variables in other scopes?

1. Traverses the queue
2. Traverses the stack
3. Finds the bugs
4. Traverse the array

✅ Correct Answer: 2

What must be done in order to implement Lexical Scoping?

1. Get the object
2. Dereference the current scope chain
3. Reference the current scope chain
4. Return the value

✅ Correct Answer: 3

What must be done in order to implement Lexical Scoping?

1. Get the object
2. Dereference the current scope chain
3. Reference the current scope chain
4. Return the value

✅ Correct Answer: 3

From which version of IE is canvas supported?

1. 6
2. 7
3. 8
4. 9

✅ Correct Answer: 4

How many parameters does the method plot() accept?

1. 7
2. 8
3. 9
4. 10

✅ Correct Answer: 3

What is the purpose of script loading?

1. Load Scripts programmatically
2. Load JavaScript files manually
3. Load JavaScript files programmatically
4. All of the mentioned

✅ Correct Answer: 3

JavaScript can be written __________

1. directly into JS file and included into HTML
2. directly on the server page
3. directly into HTML pages
4. directly into the css file

✅ Correct Answer: 1

When a class B can extend another class A, we say that:

1. A is the superclass and B is the subclass
2. B is the superclass and A is the subclass
3. Both A and B are the superclass
4. Both A and B are the subclass

✅ Correct Answer: 1

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

1. clearInvocation()
2. cancelInvocation()
3. clearInterval()
4. clear()

✅ Correct Answer: 3

The pop() method of the array does which of the following task ?

1. decrements the total length by 1
2. increments the total length by 1
3. prints the first element but no effect on the length
4. updates the element

✅ Correct Answer: 1

What will be the return value of the write() method when the Node cannot write the data immediately and has to buffer it internally?

1. 0
2. 1
3. True
4. False

✅ Correct Answer: 4

What will happen if you reference document.location from within an object?

1. Traverses the queue
2. Finds the bugs
3. Traverses the stack
4. Traverses the array

✅ Correct Answer: 3

What is a closure?

1. Function objects
2. Scope where function’s variables are resolved
3. Both Function objects and Scope where function’s variables are resolved
4. Function return value

✅ Correct Answer: 3

Which is the method invoked to connect the last vertex back to the first?

1. closePath()
2. close()
3. connectlast(first)
4. connect()

✅ Correct Answer: 1

What is the need for bubble charts?

1. Represent 2D data
2. Represent 3D data
3. Represent 2D and 3D data
4. Represents meta data

✅ Correct Answer: 2

How to get a particular value using the tagged name?

1. getElementbyID()
2. getElementsbyName()
3. getElementsbyTagName()
4. getTagName()

✅ Correct Answer: 3

Which of the following is the correct syntax to display "Letsfindcourse" in an alert box using JavaScript?

1. alert-box("Letsfindcourse"); B.
2. confirm("Letsfindcourse");
3. msgbox("Letsfindcourse");
4. alert("Letsfindcourse");

✅ Correct Answer: 4

What is the correct syntax for referring to an external script called "LFC.js"?

1. <script src="LFC.js">
2. <script source="LFC.js">
3. <script ref="LFC.js">
4. <script type="LFC.js">

✅ Correct Answer: 1

Which of the following is not Javascript frameworks or libraries?

1. Polymer
2. Meteor
3. Cassandra
4. jQuery

✅ Correct Answer: 3

Why so JavaScript and Java have similar name?

1. JavaScript is a stripped-down version of Java .
2. JavaScript's syntax is loosely based on Java's
3. They both originated on the island of Java
4. None of the above

✅ Correct Answer: 2

What is the original name of JavaScript?

1. LiveScript
2. EScript
3. Mocha
4. JavaScript

✅ Correct Answer: 3