JavaScript theory

Question 1

Set

Answer 1

A set is an unordered collection of elements without duplicate entries.

Question 2

what is javascript

Answer 2

This is what makes your site interactive and your website feel like an app

Question 3

sets are used for

Answer 3

membership testing (if a specific element belongs to the set) and eliminating duplicate entries.

Question 4

list comprehension

Answer 4

a way to create a new list with less syntax

Question 5

Iterable

Answer 5

object that can be iterated (repeated) or looped over.

Question 6

what does alert keyword do

Answer 6

pop up to gives user a message

Question 7

text string

Answer 7

string or message enclosed in quotes

Question 8

is semicolon needed in js

Answer 8

In JavaScript, the use of semicolons at the end of statements is generally optional, but it is considered a best practice to include them.

Question 9

what is a statement

Answer 9

instructions that are executed by the browser

Question 10

what is a variable

Answer 10

a word that refers to a particular value

Question 11

Variables takes on a particular value when you _______ the value to it

Answer 11

assign

Question 12

in alert if you have a number it is automatically converted to a string and displays it

Answer 12

true

Question 13

Wherever you can use a number, you can use a _____ expression.

Answer 13

math

Question 14

for n++ When the pluses come after the variable, its original value is assigned to the new variable __when____ the incrementing variable is incremented.

Answer 14

before

Question 15

what can you use to eliminate ambiguity in math expressions

Answer 15

parentheses ( )

Question 16

Using the plus operator, the code combines—_________—three elements into the
message:

Answer 16

concatenates

Question 17

if string message and number are concatenated using the + sign, what happens to the number in here

Answer 17

they are automatically converted from numbers to strings.

Question 18

A ___ box asks the user for some information and provides a response field for her
answer.

Answer 18

prompt

Question 19

To capture the user’s response you need to start by declaring a ___

Answer 19

variable

Question 20

in prompt if the user enter a number what will happen

Answer 20

its converted to a string automatically

Question 21

In prompt, If the user enters nothing and clicks OK, the variable is assigned

Answer 21

an empty string: “ “

Question 22

In prompt, If the user clicks Cancel, the variable is assigned

Answer 22

a special value, null.

Question 23

what is null

Answer 23

intentional absence of value - indicate that a variable or object property does not currently point to any meaningful value.

Question 24

what is empty string

Answer 24

a string with zero characters - used when you need a string data type, but there’s no actual textual content.

Question 25

for an if statement the condition is enclosed in

Answer 25

parentheses ( )

Question 26

just an equal = sign is reserved for

Answer 26

assigning values to a variable