Challenges Flashcards
Review and Practice (45 cards)
1
Q
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
A
44, 24, 23
2
Q
What is the output of this code? var a=8; var b=9; a=(b%2)+a/(a%3); document.write(a);
A
5
3
Q
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
A
Error
4
Q
What will be alerted?
function bar() {
return foo;
function foo() {}
var boo = '11';
}
alert(typeof bar());
undefined
function
string
number
A
Function
5
Q
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 );
A
True
6
Q
What is the output of this code?
function changeNum(b) {
b = 2;
}
var a = 3;
changeNum(a);
alert(a);
Error
2
3
undefined
A
3
7
Q
What is the output of this code?
for(var x = 0; x == x; x++) {
if(x > 5 && x < 8) {
document.write(x);
break;
}
}
A
6
8
Q
What is the output of this code?
function mult(x=10, y=2) {
return x / y;
}
document.write(mult(30));
A
15
9
Q
What is the output of this code?
if(10 > 9) {
document.write("true");
}
else {
document.write("false");
}
false
true
True
False
A
true
10
Q
You can write JavaScript code inside HTML document.
A
True
11
Q
What is the result of this code?
alert(console.log(“Solo”));
Prints “undefined” in alert box and prints “Solo” in Console.
Error
No output
A
Prints “undefined” in alert box and prints “Solo” in Console.
12
Q
What is the output?
document.write(1==”1”);
false
true
A
True
13
Q
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
A
1 1 1 1 1
14
Q
What is the data type of variable x? let x = true;
undefined
number
string
boolean
A
boolean
15
Q
What is the output of this code?
var a =”2”+”8”;
var b = a.replace(“2”,”3”);
alert(b);
A
38
16
Q
What is the output of this code?
for(var x = 1; x > 0; x++) {
if(x > 7) {
alert(x);
break;
}
}
A
8
17
Q
What is the output of this code? var a = 8; a = a + a / (a % 3); document.write(a);
A
12
18
Q
What will be alerted?
function prod(a,b,c=3) {
x=a*b*c;
return x;
}
result=prod(8,3,5);
alert(result);
A
120
19
Q
This statement is used to specify a block of code that will be executed if a specified condition is true.
- if
- unless
- or
- else
A
If
20
Q
Fill in the blanks to make the whole code block a comment. /* var a = 5; var b = 6; var sum = a+b; */
A
True
21
Q
What is the output of this code? var a = 5; var b = a % 2; a = a - b; alert(a);
A
4
22
Q
Which choice is the largest number among the options?
Options: Math.abs(16) Math.exp(16) 2017 Math.sqrt(16)
A
Math.exp(16)
23
Q
What is the output of this code? var a = "hello"; var b = 1; var c = a + b; alert(c + b);
A
hello11
24
Q
What will be alerted?
alert(“N”>”B”||”1”===1||”E”
A
True
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);
}
```
True
26
The slice() method of array prototype changes the original array.
False
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');
```
ride
28
What is the output of this code?
var x = 8 % 4;
var res = (x >= 0)?"false":"true";
alert(res);
False
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.
Yes, by using the tag.
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);
```
30
31
What is the output of this code?
let a, b;
[a, b = 6] = [2];
console.log(a + b);
```
Options:
6
2
8
10
```
8
32
```
What is the output of this code?
var s1="sololearn";
var s2="solo"+"learn";
document.write(s1 == s2);
```
True
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
```
Undefined
34
```
Fill in the blank to output 3.
var a= 9 ;
var b = 5;
b++;
alert(a - b);
```
True
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
```
objectobject
36
What is the output of this code?
var i = 1;
for (; i < 24; i += 3) {}
alert (i);
25
37
What is the output of this code?
```
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
```
Hello
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 );
}
```
True
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
```
7
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++;
}
```
678910
41
What is the output of this code?
for(var i=5; i<9; i++) {
console.log(9-i);
}
4321
42
Do anonymous functions exist in JS?
Yes
43
```
What is the output of this code?
var x=1;
for(;x<6;x+=2) {
x=x*x;
}
alert(x);
```
11
44
What is the output of this code?
alert(Math.round(5.6));
Options:
6
5
6
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.
```
No, only global variables.
