LearningFuze Mod 1 - Dom Query

Question 1

Why do we log things to the console?

Answer 1

To check and debug our code

Question 2

What is a “model”?

Answer 2

Its showing an example of something

Question 3

Which “document” is being referred to in the phrase Document Object Model?

Answer 3

Document Node

Question 4

What is the word “object” referring to in the phrase Document Object Model?

Answer 4

A collection of objects in javascript

Question 5

What is a DOM Tree?

Answer 5

It represents html objects in the nodes

Question 6

Give two examples of document methods that retrieve a single element from the DOM.

Answer 6

Documents query selector, and get element by ID

Question 7

Give one example of a document method that retrieves multiple elements from the DOM at once.

Answer 7

getElementsByClassName()

Question 8

Why might you want to assign the return value of a DOM query to a variable?

Answer 8

When you need to work with an element more than once, you should use a variable for that query, it also saves time

Question 9

What console method allows you to inspect the properties of a DOM element object?

Answer 9

the dir method

Question 10

Why would a tag need to be placed at the bottom of the HTML content instead of at the top?

Answer 10

The HTML must be read before the script, or the webpage will read the script first

Question 11

What does document.querySelector() take as its argument and what does it return?

Answer 11

It takes a CSS selector but instead of a string it returns the HTML element and what it’s holding

Question 12

What does document.querySelectorAll() take as its argument and what does it return?

Answer 12

it takes any CSS selector and it returns a static Node list

Question 13

Why do we log things to the console?

Answer 13

To check and debug our code

Question 14

What is the purpose of events and event handling?

Answer 14

An event indicates an action taking place, and the event handle deals with the event

Question 15

Are all possible parameters required to use a JavaScript method or function?

Answer 15

No

Question 16

What method of element objects lets you set up a function to be called when a specific type of event occurs?

Answer 16

the addEventListener method

Question 17

What is a callback function?

Answer 17

it calls and argument in another function

Question 18

What object is passed into an event listener callback when the event fires?

Answer 18

the event object

Question 19

What is the event.target? If you weren’t sure, how would you check? Where could you get more information about it?

Answer 19

It is the element that targets the event

Question 20

What is the difference between these two snippets of code?

element. addEventListener(‘click’, handleClick)
element. addEventListener(‘click’, handleClick())

Answer 20

The first code has the callback function and the second code is just being called.

Question 21

What is the className property of element objects?

Answer 21

Is a property that allows us to access or set value of the class for that element

Question 22

How do you update the CSS class attribute of an element using JavaScript?

Answer 22

using the className property

Question 23

What is the textContent property of element objects?

Answer 23

Allows you to update the text content of the element you are working with

Question 24

How do you update the text within an element using JavaScript?

Answer 24

Inner html or text content

Question 25

Is the event parameter of an event listener callback always useful?

Answer 25

Not always

Question 26

Would this assignment be simpler or more complicated if we didn't use a variable to keep track of the number of clicks?

Answer 26

It would be more complicated because I would have to search each time what we can use to reference a certain number

Question 27

Why is storing information about a program in variables better than only storing it in the DOM?

Answer 27

It would make us dependent on information stored on the DOM for our Javascript

Question 28

Does the document.createElement() method insert a new element into the page?

Answer 28

It does not do it

Question 29

How do you add an element as a child to another element?

Answer 29

You would use the appendChild method

Question 30

What do you pass as the arguments to the element.setAttribute() method?

Answer 30

Name and value

Question 31

What steps do you need to take in order to insert a new element into the page?

Answer 31

create the element, and then append it

Question 32

What is the textContent property of an element object for?

Answer 32

It sets or denotes the text content

Question 33

Name two ways to set the class attribute of a DOM element.

Answer 33

Can use the set attribute method and class name with is a property

Question 34

What are two advantages of defining a function to create something (like the work of creating a DOM tree)?

Answer 34

Pass in arguments and the second one is adding it to an event listener

Question 35

What is the event.target?

Answer 35

It is the point of interaction

Question 36

Why is it possible to listen for events on one element that actually happen its descendent elements?

Answer 36

by bubbling

Question 37

What does DOM element property tell you what type of element it is?

Answer 37

The tag name property

Question 38

What does the element.closest() method take as its argument and what does it return?

Answer 38

for the argument it takes selectors and for the returns itself or the matching ancestor and if it doesn't return an ancestor it will return null

Question 39

How can you remove an element from the DOM?

Answer 39

By using the remove method

Question 40

If you wanted to insert new clickable DOM elements into the page using JavaScript, how could you avoid adding an event listener to every new element individually?

Answer 40

By adding to the parent element