JS Dom Manipulation and Events

Question 1

What is the primary advantage to storing your selected elements in a variable?

Answer 1

it can be reused

Question 2

Why might you need JS to modify the DOM after the page loads?

Answer 2

gives user interactivity

Question 3

How can you better prepare when writing HTML for DOM manipulation in your JS code?

Answer 3

set ID and class attribues

Question 4

What are the differences between innertext and textContent?

Answer 4

innertext will show what is seen, and textContent will give you everything

Question 5

What datatypes are the values you remove from a text input?

Answer 5

anything you want updated

Question 6

Why is it so important to be able to dynamically update text

Answer 6

in response to users

Question 7

What are some of the drawbacks of HTML Event Handler Attributes?

Answer 7

code is mixed with HTML which makes the code more difficult to maintain and extend. Timing issue as well.

Question 8

Why is the Window.event property to be avoided in new code?

Answer 8

because it changes with every event and becomes chaotic

Question 9

Why is the Window.event property useful for finding and element which was interacted with?

Answer 9

gives us a direct channel to that element

Question 10

What is the difference between getElementById and querySelector?

Answer 10

query selector will receive a css selector and get element by Id is only ids

Question 11

Who passes in the event object into the handleClick callback function?

Answer 11

the JS language

Question 12

Does a callback function require a name?

Answer 12

NO

Question 13

What is the purpose of a loop?

Answer 13

loops checks a condition and repeats until the condition returns false.Lets you repeat functionality

Question 14

Why might there be different kinds of loops?

Answer 14

depending on the situation. if you do not know how many times the code should run use a while loop, and if you need to run a code at a specific number of times use a for loop

Question 15

What is the purpose of a conditional expression as it relates to loops?

Answer 15

indicator when we are finished

Question 16

Could a loop potentially go on forever?

Answer 16

Yes

Question 17

Could a loop never start?

Answer 17

Yes, if you don’t configure them right

Question 18

How does a for loop differ from a while loop?

Answer 18

while loops only need the end point and for loop are useful for knowing exactly how many times you need to use it

Question 19

What potential use cases are there for for loop?

Answer 19

for a search in a search engine. for arrays

Question 20

Which pieces of info provided in the parenthesis for a for loop are mandatory?

Answer 20

none of them are mandatory

Question 21

What is a for in loop?

Answer 21

loops through the properties of an object

Question 22

How do you target the value of a property in an object?

Answer 22

bracket notation

Question 23

When should you use a for in loop?

Answer 23

if you need to loop over an object

Question 24

What is the difference between the parentNode and parentElement properties?

Answer 24

parent node could be an element and could be a node or something other than an element, parent element is for elements. Parent element is what you are gonna be looking for for the most part

Question 25

Why is it important to be able to traverse the DOM?

Answer 25

allows us to find information on elements around us and to make the search more efficient. avoid white space also

Question 26

What kind of information is useful to store in custom attributes?

Answer 26

attaching data that ties that element in JS and pull the info off the element itself

Question 27

What are two ways to target elements on the DOM?

Answer 27

getElementbyId, querySelector

Question 28

What is another way to add a text node to an element other using TextContent

Answer 28

innertext, document.createtextnode, avoid innerHTML

Question 29

How do you create a HTML element using vanilla Javascript?

Answer 29

the createlement method of the document object

Question 30

Why is using loops and arrays for creating multiple dom elements preferable to creating them one at a time?

Answer 30

DRY. code looks less dense and makes code processing more efficient

Question 31

Why are arrays preferred over objects for the functionality referenced in question 1?

Answer 31

because it will be in order based on the index

Question 32

Why is it important to be able to retrieve and use data from inputs?

Answer 32

our ability to communicate with the user

Question 33

Why is it dangerous to assume you have to correct data when creating element?

Answer 33

to have proper data for the proper job

Question 34

What is event bubbling?

Answer 34

for any element in HTML, if an event occurs inside that element, due to bubbling every element is also clicked. based on HTML structure and not visuals

Question 35

What is the difference between event.target and event.currentTarget?

Answer 35

target refers to node(where user clicked) , currentTarget on the opposite refers to the node on which current-event listener was attached

Question 36

What is the first argument the function setTimout takes?

Answer 36

it take a callback function as its first aregument

Question 37

If the second argument is not passed into setTimout function, what is the default value?

Answer 37

Zero

Question 38

What are some scenarios where setTimeout can be useful?

Answer 38

pop ups, see if the user is still there

Question 39

What does the setInterval function return?

Answer 39

it returns an interval ID that identifies the interval

Question 40

What arguments does the clearnInterval function take?

Answer 40

ID variable value of the setInterval

Question 41

what is the event loop?

Answer 41

it makes asyncranous doable outside of a call stack

Question 42

what does the term blocking mean?

Answer 42

execution of additional js must wait until the call stack is clear

Question 43

What is the call stack?

Answer 43

is an interpreter to keep track of its place

Question 44

which element in a website are useful to create dynamically?

Answer 44

instagram of google search. | like a div. typcally to respond to user input

Question 45

Why should you not create all elements dynamically?

Answer 45

might be harder to read html doc

Question 46

What is a modal?

Answer 46

a scripted effect that allows you to overlay a small element over a website

Question 47

What are some use cases for modals?

Answer 47

error, warning, data, confirm or prompt, chat popper

Question 48

Why does a modal usually need to occupy the entire height and width of the viewport?

Answer 48

because you dont want the user to be able to click on anything

Question 49

Give two examples of media features that you can query in an @media rule.

Answer 49

resizing images such as min-width and max-width

Question 50

Which HTML meta tag is used in mobile-responsive web pages?

Answer 50

viewport meta tag which contains content and initial scale attributes