QUIZ ON : javascript - JS BASIC SYNTAX AND DATA TYPES

JS BASIC SYNTAX AND DATA TYPES

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Question No# : 01 out of 30

For testing we should use

A. document. write()

B. console.log()

C. window. alert()

D. innerHTML

Question No# : 02 out of 30

<p>What type of value gets printed if we add the following two variables ? </p><pre>var a = "10";<br>var b =50;</pre>

A. Long

B. Text

C. Integer

D. Number

Question No# : 03 out of 30

JavaScript numbers are stored as

A. integers

B. double precision floating point

C. double

D. floating point

Question No# : 04 out of 30

Which of the following is true about the <script> tag in HTML?

A. Multiple <script> tags can be used in the same HTML document

B. The <script> tag can only be placed in the <head> section

C. The <script> tag can only be used once in an HTML document

D. The <script> tag must always reference an external file

Question No# : 05 out of 30

What is the output of this expression? x = 2 + 2; document.write(x);

A. 22

B. 4

C. 2

D. syntax error

Question No# : 06 out of 30

<p>what will be the output of </p><pre>document.write("5" + 5)</pre>

A. 5

B. 10

C. 55

D. error

Question No# : 07 out of 30

What does the console.log() function do?

A. Displays a message in an alert box

B. Prints output to the console

C. Writes data to a file

D. Logs an error in the browser console

Question No# : 08 out of 30

Which operator is used to assign a value to a variable?

A. =

B. x

C. ==

D. *

Question No# : 09 out of 30

When there is an indefinite or an infinity value during an arithmetic value computation in javascript

A. Prints an exception error

B. Prints an overflow error

C. Displays “Infinity”

D. Prints the value as such

Question No# : 10 out of 30

Which method is not used for converting variables to number?

A. parseInt ()

B. Number()

C. parseFloat()

D. valueOf()

Question No# : 11 out of 30

Which keyword is a must to use when JavaScript code is to run in older browser?

A. var

B. let

C. const

D. none of the above

Question No# : 12 out of 30

While working on a JavaScript project, in your JavaScript application, which function would you use to send messages to users requesting for text input?

A. Display()

B. Prompt()

C. Alert()

D. Confirm()

Question No# : 13 out of 30

How can you add a comment in a JavaScript?

A.

B. //This is a comment

C. 'This is a comment

D. #This is a comment

Question No# : 14 out of 30

Which one of the following is not considered as an error

A. Division by zero

B. Missing of semicolons

C. Syntax error

D. Both A and B

Question No# : 15 out of 30

How do you declare a JavaScript variable?

A. variable carName;

B. var carName;

C. vari carName;

D. dim carName;

Question No# : 16 out of 30

What is "this" in JavaScript:

A. keyword

B. function

C. Declaration Statement

D. Data type

Question No# : 17 out of 30

What is the correct way to embed JavaScript directly within an HTML file?

A. <script href="script.js"></script>

B. <script> alert('Hello, World!'); </script>

C. <js> alert('Hello, World!'); </js>

D. <style> alert('Hello, World!'); </style>

Question No# : 18 out of 30

The type of a variable that is volatile is

A. Volatile variable

B. Mutable variable

C. Immutable variable

D. Dynamic variable

Question No# : 19 out of 30

How do you correctly link an external JavaScript file to an HTML document?

A. <script src="script.js"></script>

B. <javascript src="script.js"></javascript>

C. <link href="script.js" rel="script">

D. <script href="script.js"></script>

Question No# : 20 out of 30

The correct syntax to write "Sky is blue" in JavaScript is

A. jscript.write("Sky is blue")

B. document.write("Sky is blue")

C. print("Sky is blue")

D. jscript.print("Sky is blue")

Question No# : 21 out of 30

Which of the following is/are valid javascript data types?

A. Null type

B. Undefined type

C. Number type

D. All of the mentioned

Question No# : 22 out of 30

For displaying data in JavaScript, we can’t use _

A. document. write()

B. console.log()

C. innerHTML

D. document.getElementById()

Question No# : 23 out of 30

The snippet that has to be used to check if “a” is not equal to “null” is

A. if(a!=null)

B. if (!a)

C. if(a!null)

D. if(a!==null)

Question No# : 24 out of 30

Which of the following is true about the placement of JavaScript in HTML?

A. JavaScript must always be placed inside the <head> tag

B. JavaScript can be placed either in the <head> or <body> tag

C. JavaScript can only be placed in external files

D. JavaScript cannot be placed in the <head> tag

Question No# : 25 out of 30

Which statement specify correct difference between var and let keywords in JavaScript?

A. var defines a variable while let defines a constant.

B. There is no such major difference between them

C. The value of variable declared with let cannot be changed

D. var define function scoped variable while let define block scoped variable

Question No# : 26 out of 30

Which operator is used to assign a value to a variable in JavaScript?

A. =

B. ==

C. ===

D. !=

Question No# : 27 out of 30

Which of the following is not a JavaScript datatype?

A. Boolean

B. String

C. Number

D. Function

Question No# : 28 out of 30

How do you write a comment in JavaScript?

A. //This is a comment

B.

C. /* This is a comment */

D. Both A and C

Question No# : 29 out of 30

Which statement specify correct difference between var and let keywords in JavaScript ?

A. var defines a variable while let defines a constant.

B. There is no such major difference between them.

C. The value of a variable declared with var can be changed while the value of a variable declared with let cannot be changed.

D. var defined function scoped variable while let define block scoped variable.

Question No# : 30 out of 30

Which of the following is not a valid JavaScript variable name?

A. 5myvalue

B. myvalue5

C. Myvalue

D. None of These