JavaScript 1.1

Question 1

Define Javascript

Answer 1

“An object-oriented computer programming language commonly used to create interactive effects within web browsers.” -Oxford

Question 2

What’s the difference between an interpreted language vs a compiled language?

Answer 2

In a compiled language, the target machine directly translates the program. In an interpreted language, the source code is not directly translated by the target machine. Instead, a different program, aka the interpreter, reads and executes the code.

Question 3

Define object-oriented programming

Answer 3

Object-oriented programming is a model that organizes software design around data or objects rather than function or logic

Question 4

Define using variables

Answer 4

Variables are used as containers for storing data (values)

Question 5

Define API

Answer 5

An application programming interface is a connection between computers or between computer programs. It is a type of software interface, offering a service to other pieces of software.

Question 6

What can we use to add special characters within strings?

Answer 6

\ the escape character

Question 7

Boolean has two values :

Answer 7

true or false

Question 8

What happens when you place an increment after a given value?

Answer 8

It returns the original value and then the increment. Placing it before will just give us the incremented value.

Question 9

What does var x += y mean?

Answer 9

x = x + y

Question 10

Explain what these three are and what they mean! ‘ &&, II, and !’

Answer 10

These are logical operators; && returns true if both ops are true, II returns true if one op is true and ! returns true if the op is false and vice versa

Question 11

A Javascript function is:

Answer 11

a block of javascript code, that can be executed when “called” for

Question 12

Create external script that would be placed in a HTML document

Answer 12

script tag, add the source attribute, and then call for js file

Question 13

In what situations do we use the document.write() function

Answer 13

For testing only, all other existing html gets deleted

Question 14

Javascript programming is a list of:

Answer 14

“statements”

Question 15

When it comes to variables, if you want your code to run on old browsers you must use:

Answer 15

“var” keyword

Question 16

A variable used for values that don’t change

Answer 16

“const” variable

Question 17

If you think the variable can change use:

Answer 17

“let” keyword

Question 18

List 2 facts about identifiers

Answer 18

Reserved Javascript words cannot be used to declare variables. Underscores and the money character can be used at the beginning of an identifier.

Question 19

Variables defined with let have blockscope which means?

Answer 19

variables declared with in a block cannot be accessed outside of {}

Question 20

“let” and “const” variables cannot be redeclared TRUE OR FALSE

Answer 20

TRUE

Question 21

“var” and “const”variables cannot be redeclared TRUE OR FALSE

Answer 21

FALSE

Question 22

What’s a better way to redeclare a variable using “let”?

Answer 22

let x = 10; {let x = 2;} //x will still have the value of 10

Question 23

“const” variables can be reassigned TRUE OR FALSE

Answer 23

FALSE

Question 24

Name three popular data types in JavaScript

Answer 24

Strings, Objects, Numbers

Question 25

What will 16 + “Volvo” return in a js expression?

Answer 25

16Volvo (JavaScript converts numbers into strings in JS arithmetic)

Question 26

Array indexes are zero-based which means:

Answer 26

The first item is an array starts at 0, the second would be one, and so on…

Question 27

Describe the content that goes within an JS Object

Answer 27

JS Objects are written in curly {}, the properties are written in name:value pairs

Question 28

A variable without a value has the value of:

Answer 28

Undefined

Question 29

(Js Objects) a method is a

Answer 29

Function stored as a property

Question 30

The JavaScript "this":

Answer 30

keyword refers to the object it belongs to.

Question 31

declare a Object method

Answer 31

objectName.methodName()