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JavaScript Objective Questions - 48

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Question: 1

Which one is standard way to show popup in Java Script?

(A) window.alert("cppbuzz");
(B) alert("cppbuzz");
(C) window("cppbuzz");
(D) alert("cppbuzz")

Level: Beginner Category: methods
[Posted by: Admin | Chicago, USA]

Question: 2

Javascript string using double quotes is exactly the same as a string using single quotes

(A) True
(B) False

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 3

What is the output of following Javascript?

var a = 'cpp';
var b = 'buzz';
var c = a/b;
document.write(c);

(A) cppbuzz
(B) cpp/buzz
(C) NaN
(D) None of the above

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 4

Find output of below code

var a = '10';
var b = a = 20;
document.write(a+b);

(A) Error in Script
(B) '10'20
(C) 1020
(D) 40

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 5

What is divide by 0 in Javascript?

var a = 10;
var b = 0;
document.write(a/b);

(A) Nothing is printed
(B) 0 is printed
(C) Infinity is printed
(D) Some Garbage Value

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 6

What is default value of any variable in Javascript?

var a;
document.write(a);

(A) 0
(B) undefined
(C) error
(D) NaN

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 7

How ++ works in Javascript? Find output of below Javascript code.

var a = 10;
document.write(a++);
document.write(a);

(A) 1111
(B) 1110
(C) 1010
(D) 1011

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 8

Find output of below Javascript code

var a = 10;
document.write(a=20);

(A) Error
(B) Nothing is printed
(C) 10
(D) 20

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 9

Find output of below Javascript addition code

document.write("2 plus 2 is " + 2 + 2);

(A) 4
(B) 2 plus 2 is 4
(C) 2 plus 2 is 22
(D) 2 plus 2 is 2 + 2

Level: Beginner Category: operators
[Posted by: Admin | Chicago, USA]

Question: 10

Find output of below Javascript code

<script>
document.write(2+2 + " = 2 plus 2");
</script>

(A) 2+2+ = 2 plus 2
(B) 4 + = 2 plus 2
(C) 4 = 2 plus 2
(D) Syntax Error

Level: Beginner Category: variables
[Posted by: Admin | Chicago, USA]

Question: 11

A prompt box asks the user for some information and provides a response field for the answer

(A) True
(B) False

Level: Practitioner Category: methods
[Posted by: Admin | Chicago, USA]

Question: 12

What is the output of below Javascript code if user keeps the default value of prompt box?

<script>
var question = "Your species?";
var defaultAns = "human";
var out = prompt(question, defaultAns);
document.write(out);
</script>

(A) Nothing is printed
(B) human
(C) Error
(D) NaN

Level: Expert Category: other
[Posted by: Admin | Chicago, USA]

Question: 13

We can use the === (equality) operator to compare a variable with a string, Can we use it to compare two numbers?

(A) Yes
(B) No

Level: Practitioner Category: operators
[Posted by: Admin | Chicago, USA]

Question: 14

What if we put ; after if? does it really affect? Find the output of below Javascript

<script>
 var a = 10;
 if(a == 20);
 document.write(a);
</script>

(A) Error
(B) Nothing is printed
(C) 20
(D) 10

Level: Beginner Category: conditional
[Posted by: Admin | Chicago, USA]

Question: 15

What if we put ++ operator inside if condition?  find the output of below code

<script>
var a = 10;
if(a == a++)
document.write(a);
</script>

(A) Error
(B) Nothing is printed
(C) 10
(D) 11

Level: Practitioner Category: conditional
[Posted by: Admin | Chicago, USA]

Question: 16

Find the output of below Javascript

<script>
var a = 10;
if(a == a++);
{
document.write(a);
}
</script>

(A) 10
(B) 11
(C) Nothing is printed
(D) Error

Level: Practitioner Category: conditional
[Posted by: Admin | Chicago, USA]

Question: 17

Find the output of below for loop in Javascript

<script>
for(var i=0;i<5;i++)
{
    document.write(i++);
}
</script>

(A) 01234
(B) 012345
(C) 135
(D) 024

Level: Beginner Category: loops
[Posted by: Admin | Chicago, USA]

Question: 18

Can we put ; after for loop in Javascript? find the output of below code

<script>
for(var i=0;i<5;i++);
{
    document.write(i++);
}
</script>

(A) 024
(B) 135
(C) Compilation Error
(D) 5

Level: Practitioner Category: loops
[Posted by: Admin | Chicago, USA]

Question: 19

Is it mandatory to put all three conditions in for loop? find the output of below Javascript code

<script>
for(var i=0;i++<5; )
{
    document.write(i);
}
</script>

(A) 01234
(B) 12345
(C) 1234
(D) Compilation Error

Level: Practitioner Category: loops
[Posted by: Admin | Chicago, USA]

Question: 20

Is it mandatory to put all three conditions in for loop? find the output of below Javascript code

<script>
for(var i=0;i++<5; )
{
    document.write(i);
}
</script>

(A) 01234
(B) 12345
(C) 1234
(D) Compilation Error

Level: Practitioner Category: loops
[Posted by: Admin | Chicago, USA]

Question: 21

Example of arrays in Javascript. Find output of below code

<script>
var firstNames = ["c", "c++", "java", "python", "perl"];
for (var i = 0; i < firstNames.length; i++) {
if(i%2===0)
continue;
document.write(i);
}
</script>

(A) 012345
(B) 01234
(C) 135
(D) 13

Level: Practitioner Category: arrays
[Posted by: Admin | Chicago, USA]

Question: 22

Can we create empty array in Javascript? Find the output of below code

<script>

var firstNames = []; //creating empty array

for (var i = 0; i <=firstNames.length; i++) {
document.write("Javascript");
}

</script>

(A) Error
(B) Nothing is printed
(C) Javascript
(D) JavascriptJavascript

Level: Practitioner Category: arrays
[Posted by: Admin | Chicago, USA]

Question: 23

Math.ceil() and Math.floor() are methods which are used with number. How Javascript behaves when any character is passed instead of numbers? like 

<script>
var mathVal = Math.floor('f');
document.write(mathVal);
</script>

(A) It is Error
(B) Nothing is printed
(C) 0 is the output
(D) NaN is the output

Level: Expert Category: methods
[Posted by: Admin | Chicago, USA]

Question: 24

What is the output of Math.ceil(0) in Javascript?

<script>
var mathVal = Math.ceil(0);
document.write(mathVal);
</script>

(A) 1
(B) 0
(C) NaN
(D) None of the above

Level: Expert Category: methods
[Posted by: Admin | Chicago, USA]

Question: 25

Find the output of below code

<html>
<head>
<title>JavaScript Example</title>
 
<script type="text/javascript">
function getHeader() {
    return "<h1>Javascript Questions</h1>"
}
</script>

</head>
<body>
<script type="text/javascript">
    document.write(getHeader());
</script>

</body>
</html>

(A) <h1>Javascript Questions</h1>
(B) Javascript Questions
(C) Error
(D) "<h1>Javascript Questions</h1>"

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JavaScript Objective Questions - 48

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