Challenges

Question 1

Choose the numbers that are NOT present in this code’s output.
for(let i = 10; i <= 15; i++)
document.write(45 - i + “,”);
Select all that apply

44
34
24
23

Answer 1

44, 24, 23

Question 2

What is the output of this code?
var a=8;
var b=9;
a=(b%2)+a/(a%3);
document.write(a);

Answer 2

5

Question 3

What is the output of this code?
var arr = [5, 6, 8];
var str = (string)arr;
var bool = (boolean)str;
console.log(bool);

True
False
Error

Answer 3

Error

Question 4

What will be alerted? 
function bar() {
  return foo;
  function foo() {} 
  var boo = '11';
}
alert(typeof bar());

undefined
function
string
number

Answer 4

Function

Question 5

Fill in the blanks to change the content of the div to “Hi there”.

<div></div>

var d,a;
d=document.getElementById(‘ txt ‘);
a=document.createTextNode(“Hi there”);
d .appendChild( a );

Answer 5

True

Question 6

What is the output of this code?
function changeNum(b) {
  b = 2;
}
var a = 3;
changeNum(a);
alert(a); 

Error
2
3
undefined

Answer 6

3

Question 7

What is the output of this code?
for(var x = 0; x == x; x++) {
  if(x > 5 && x < 8) {
    document.write(x);
    break;
  }
}

Answer 7

6

Question 8

What is the output of this code?
function mult(x=10, y=2) {
  return x / y;
}
document.write(mult(30));

Answer 8

15

Question 9

What is the output of this code? 
if(10 > 9) {
  document.write("true");
}
else {
  document.write("false");
}  
false  
true  
True  
False

Answer 9

true

Question 10

You can write JavaScript code inside HTML document.

Answer 10

True

Question 11

What is the result of this code?
alert(console.log(“Solo”));

Prints “undefined” in alert box and prints “Solo” in Console.

Error

No output

Answer 11

Prints “undefined” in alert box and prints “Solo” in Console.

Question 12

What is the output?
document.write(1==”1”);
false
true

Answer 12

True

Question 13

What is the output of this code?
var nums = [1, 2, 3, 4, 5];
var str = "";
for(var i = 0; i < 5; i++) {
  str += nums[i] + " ";
  nums.unshift(1);
}
console.log(str);

1 1 2 3 4
5 4 3 2 1
1 1 1 1 1
1 2 3 4 5

Answer 13

1 1 1 1 1

Question 14

What is the data type of variable x?
let x = true;  

undefined
number
string
boolean

Answer 14

boolean

Question 15

What is the output of this code?
var a =”2”+”8”;
var b = a.replace(“2”,”3”);
alert(b);

Answer 15

38

Question 16

What is the output of this code?
for(var x = 1; x > 0; x++) {
  if(x > 7) {
     alert(x);
     break;
  }
}

Answer 16

8

Question 17

What is the output of this code?
var a = 8;
a = a + a / (a % 3);
document.write(a);

Answer 17

12

Question 18

What will be alerted?
function prod(a,b,c=3) {
  x=a*b*c;
  return x;
}
result=prod(8,3,5);
alert(result);

Answer 18

120

Question 19

This statement is used to specify a block of code that will be executed if a specified condition is true.

• if
• unless
• or
• else

Answer 19

If

Question 20

Fill in the blanks to make the whole code block a comment.  
/*   var a = 5;  
var b = 6;  
var sum = a+b;   */

Answer 20

True

Question 21

What is the output of this code?
var a = 5;
var b = a % 2;
a = a - b;
alert(a);

Answer 21

4

Question 22

Which choice is the largest number among the options?

Options:
Math.abs(16)  
Math.exp(16)  
2017  
Math.sqrt(16)

Answer 22

Math.exp(16)

Question 23

What is the output of this code? 
var a = "hello";
var b = 1;
var c = a + b;
alert(c + b);

Answer 23

hello11

Question 24

What will be alerted?

alert(“N”>”B”||”1”===1||”E”

Answer 24

True

Question 25

Fill in the blanks to output all the EVEN numbers in the range 50 to 120.

for  (var i=50; i<=  120  ;   
i+=  2  ) {  
  document.write(i);
}

Answer 25

True

Question 26

The slice() method of array prototype changes the original array.

Answer 26

False

Question 27

What is the output of this code?
var car = {
  color: 'green',
  wheels: 4,
  riding: false
};
car.riding =
  car.wheels === car['wheels'] ? true : false;
if(car.riding)
  console.log('ride');
else
  console.log('stop');

Answer 27

ride

Question 28

What is the output of this code?
var x = 8 % 4;
var res = (x >= 0)?”false”:”true”;
alert(res);

Answer 28

False

Question 29

Can you write JS code directly in an HTML file?

No, because JS code needs its own file.
No, because JS is never compatible with HTML.
Yes, by using the tag.
Yes, by using the tag.

Answer 29

Yes, by using the tag.

Question 30

What is the output of this code?
var a = 5;
var b = a * 5;
var c;
if (a > 2)
  c = a + b;
else
  c = b - a;
console.log(c);

Answer 30

30

Question 31

What is the output of this code?
let a, b;
[a, b = 6] = [2];
console.log(a + b);

Options:
6  
2  
8  
10

Answer 31

8

Question 32

What is the output of this code? 
var s1="sololearn";
var s2="solo"+"learn";
document.write(s1 == s2);

Answer 32

True

Question 33

What is the output of this code?
var numbers = [44, 55, 66, 12, 67, 89];
console.log(numbers[numbers.length]);

Options:
undefined  
67  
89  
12

Answer 33

Undefined

Question 34

Fill in the blank to output 3.  
var a=   9  ;  
var b = 5;
b++;
alert(a - b);

Answer 34

True

Question 35

What will be alerted?
var solo1 = [1, 2];
var solo2 = new Array(1, 2);
alert(typeof(solo1) + typeof(solo2));  

Options:
objectarray  
arrayobject  
arrayarray  
objectobject

Answer 35

objectobject

Question 36

What is the output of this code?
var i = 1;
for (; i < 24; i += 3) {}
alert (i);

Answer 36

25

Question 37

What is the output of this code?

<p><a>hi</a></p>

  var p=document.getElementById('p'); 
  var a=document.getElementById('a'); 
  var t=document.createTextNode('Hello');
  p.removeChild(a);
  p.appendChild(t);

Options:
Hello  
hi  
nothing  
a

Answer 37

Hello

Question 38

Fill in the blanks to output the value of x, if it is even.

var x = 8;  
if  (x  %  2 == 0) {  
  document.write(  x  );  
}

Answer 38

True

Question 39

What is the output of this code?
function*x() {
  var y = 8 - (yield 8);
  return y;
}
var u = x();
u.next().value;
console.log(`${u.next(1).value}`);  

Options
Error  
0  
16  
7

Answer 39

7

Question 40

What is the output of this code? 
var a=[3,17,35,51,89];
var b=a[3] % 9;
while (b < 11) {
   document.write(b);
   b++;
}

Answer 40

678910

Question 41

What is the output of this code?
for(var i=5; i<9; i++) {
console.log(9-i);
}

Answer 41

4321

Question 42

Do anonymous functions exist in JS?

Answer 42

Yes

Question 43

What is the output of this code?
var x=1;
for(;x<6;x+=2) {
  x=x*x;
}
alert(x);

Answer 43

11

Question 44

What is the output of this code?
alert(Math.round(5.6));

Options:
6
5

Answer 44

6

Question 45

Does global object window contain all variables as properties?

Options: 
No, only local variables.  
No, variables are not properties of the global object.  
No, only global variables.  
Yes, all variables.

Answer 45

No, only global variables.