Intro to JavaScript

Question 1

it is an object-oriented, dynamically typed scripting language

Answer 1

JavaScript

Question 2

is dynamically typed (also called weakly typed) in that variables can be easily (or implicitly) converted from one data type to another.

Answer 2

JavaScript

Question 3

refers to the client machine (i.e., the browser) running code locally rather than relying on the server to execute code and return the result.

Answer 3

Client Side Scripting

Question 4

Processing can be off-loaded from the server to client machines, thereby reducing the load on the server.

Answer 4

client-side scripting

Question 5

The browser can respond more rapidly to user events than a request to a remote server ever could, which improves the user experience.

Answer 5

client-side scripting

Question 6

was introduced by Netscape in their Navigator browser back in 1996.

Answer 6

JavaScript

Question 7

JavaScript was originally called what?

Answer 7

LiveScript

Question 8

at first did not support JavaScript but instead had its own browser-based scripting language (VBScript).

Answer 8

Internet Exp;orer

Question 9

is simultaneously a superset and subset of the JavaScript programming language.

Answer 9

ECMAScript

Question 10

the one that introduced many notable new additions to the language (such as
classes, iterators, arrow functions, and promises).

Answer 10

The Sixth Edition (or ES6)

Question 11

enabled sites that JavaScript became a much more important part of web development.

Answer 11

AJAX

Question 12

has almost completely displaced XML as the most common format for data transport in interactive web sites, thus making the AJAX acronym less and less meaningful today.

Answer 12

JSON

Question 13

has migrated into other nonbrowser applications. It can be used as the language within server-side runtime environments such as Node.js

Answer 13

JavaScript

Question 14

Some newer non-relational database system use JavaScript as their query language

Answer 14

MongoDB

Question 15

use JavaScript as their end-user scripting language

Answer 15

Adobe Creative Suite and OpenOffice

Question 16

make use of an embedded JavaScript engine.

Answer 16

Oculus Rift headset and the Arduino and Raspberry Pi microcontrollers

Question 17

of libraries of JavaScript functions and objects are generally referred to as

Answer 17

JavaScript Frameworks

Question 18

simplify the process of creating Single-Page Applications (SPA)

Answer 18

React and Vue.js

Question 19

allow developers to construct applications using software engineering best practices

Answer 19

Angular and Ember

Question 20

refers to the practice of including JavaScript code directly within some HTML element attributes

Answer 20

Inline JavaScript

Question 21

refers to the practice of placing JavaScript code within a

 element

Answer 21

Embedded JavaScript

Question 22

It’s function-scoped or global-scoped and gets hoisted (moved to the top of its scope).

Answer 22

var

Question 23

Declares a block-scoped variable that can be reassigned.

Answer 23

let

Question 24

Declares a block-scoped variable that cannot be reassigned. It can hold objects/arrays, but their contents can change.

Answer 24

const

Question 25

instructs the browser to display a pop-up or modal dialog window

Answer 25

alet()

Question 26

can be a useful way to output markup content from within JavaScript.

Answer 26

document.write()

Question 27

often used to output markup or to combine markup with JavaScript variables

Answer 27

document.write()

Question 28

displays content with a browser controlled pop-up/modal window

Answer 28

alet()

Question 29

display content in the browser's JavaScript console

Answer 29

console.log

Question 30

displays a message and an input field within a modal window

Answer 30

prompt()

Question 30

outputs the content (as markup) directly to the HTML document

Answer 30

document.write()

Question 31

displays a question in a modal window with ok and cancel buttons

Answer 31

confirm()

Question 32

usually referred to as objects

Answer 32

reference types

Question 33

nonobject, simple types

Answer 33

primitive types

Question 34

Stores true or false values.

Answer 34

boolean

Question 35

Represents numeric values (includes integers and decimals). Uses 64-bit floating point format.

Answer 35

Number

Question 36

A sequence of characters enclosed in single (') or double (") quotes

Answer 36

String

Question 37

Has only one value:null

Answer 37

null

Question 38

Value given to uninitialized variables. Different from null.

Answer 38

Undefined

Question 39

represents a unique value that can be used as a key value.

Answer 39

Symbol

Question 40

contain the value of the primitive directly within memory.

Answer 40

Primitive variables

Question 41

contain a reference or pointer to the block of memory associated with the content of the object

Answer 41

object variables

Question 42

Newer versions of JavaScript have added an alternative technique for concatenation

Answer 42

Template literals

Question 43

to combine string literals together with other variables

Answer 43

+

Question 44

are used to execute a code block repeatedly. JavaScript defines three principal statements for executing loops

Answer 44

Loops

Question 45

is a data structure that allows the programmer to collect a number of related elements together in a single variable

Answer 45

Array

Question 46

To add an item to the end of an existing array

Answer 46

push()

Question 47

To add an item at the beginning of an existing array

Answer 47

unshift()

Question 48

can be used to remove the last element from an array.

Answer 48

pop()

Question 49

provides a new way to create an array from one or more existing arrays.

Answer 49

spread syntax

Question 50

introduced an alternate way to iterate through an array

Answer 50

for...of loop

Question 51

provides a simplified syntax for extracting multiple scalar values from an array

Answer 51

array destructuring

Question 52

To reference the object properties

Answer 52

dot notation (objName.property) and square bracket notation obj.Name["property1"]

Question 53

is used as a language-independent data interchange format analogous in use to XML.

Answer 53

JSON

Question 54

convert the JSON string into an actual array

Answer 54

JSON.parse()

Question 55

are the building blocks for modular code in JavaScript.

Answer 55

Functions

Question 56

function expression without function name

Answer 56

anonymous function

Question 57

ES6 added a new syntax for declaring functions

Answer 57

arrow syntax

Question 58

provide a more concise syntax for the definition of anonymous functions.

Answer 58

arrow syntax

Question 59

They also provide a solution to a potential scope problem encountered with the this keyword in callback functions

Answer 59

arrow syntax

Question 60

generally refers to the context in which code is being executed.

Answer 60

Scope

Question 61

variables defined within an if {} block or a for {} loop block using the let or const keywords are only available within the block in which they are defined.

Answer 61

block-level scope

Question 62

if an identifier has this scope, it is available everywhere

Answer 62

global scope

Question 63

is actually an object consisting of the scope environment in which the function is created

Answer 63

closure

Question 64

a function that has an implicitly permanent link between itself and its scope chain.

Answer 64

closure