Dom-querying-Q&A

Question 1

Why do we log things to the console?

Answer 1

console. log specifically is a method for developers to write code to inconspicuously inform the developers what the code is doing.

Question 2

What is a “model”?

Answer 2

The model is called a DOM tree, and it is stored in the browsers’ memory.
It consists of four main types of nodes.

Question 3

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

Answer 3

When the browser loads a web page, it
creates a model of the page in memory.
The DOM specifies the way in which the
browser should structure this model using
a DOM tree

Question 4

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

Answer 4

object model” is used in the traditional object oriented design sense: documents are modeled using objects, and the model encompasses not only the structure of a document, but also the behavior of a document and the objects of which it is composed.

Question 5

What is a DOM Tree?

Answer 5

The DOM is called an object model
because the model (the DOM tree) is
made of objects.
Each object represents a different part of
the page loaded in the browser window.

Question 6

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

Answer 6

getElementByld(‘id’)

querySelector( ‘css selector’)

Question 7

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

Answer 7

getElementsByClassName( ‘class’ )

Question 8

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

Answer 8

It saves the browser from having to look through the DOM tree and search for the same elements again and a again

Question 9

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

Answer 9

Console.dir()

Question 10

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

Answer 10

When you place your JavaScript at the bottom of your HTML body, it gives the HTML time to load before any of the JavaScript loads, which can prevent errors, and speed up website response time.

Question 11

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

Answer 11

the first Element within the document that matches the specified selector, or group of selectors. If no matches are found, null is returned.

Question 12

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

Answer 12

a static (not live) NodeList representing a list of the document’s elements that match the specified group of selectors.