02. Retrieving a single element and DOM traversal

When selecting elements from the DOM, we can either select one or many nodes. Let's start with retrieving a single element.

To retrieve an element, we use DOM queries. These are the methods used through JavaScript that we can use to find elements on the DOM tree. Oftentimes, the elements we select are stored into a variable, which serves as a reference to the node; this is known as caching.

getElementById

The most efficient way to obtain an element is through its id attribute. We may do this with the getElementById() method, in which we simply pass in the name of the id. Since we know that no two elements can share the same id, we are ensured that the browser terminates right after finding the first id, resulting in quickness and responsivity.

var firstItem = document.getElementById('first')

This command will store the reference to the element with an id of first within the firstItemvariable.

querySelector

Another way to select just one element is through a query selector. Given a CSS selector, this returns only the first matched item.

firstParagraph = document.querySelector('p') # First 

tag. document.querySelector('.item') # First element with a class "item"

Traversing the DOM - single elements

Once we have selected a single element, we may access the nodes around it through these properties:

parent
Select parent of current node.
previousSibling
Select the previous sibling node.
nextSibling
Select the next sibling node.
firstChild
Select the first child of current element.
lastChild
Select last child of current element.

Aching back from coding all day?

Prism Glasses

Aching back from coding all day? Try Back Problems

Ever feel achy from sitting crunched up on your computer table? Try lying down with these optical glasses that allow you to work on your laptop while lying flat on your back. This is the perfect solution with those with limited mobility or those who wish to prevent neck cramps and back strains.

$ Check price
4.454.45Amazon 4 logo(128+ reviews)

More Back Problems resources

Build modern and responsive webpages

Responsive Typography

Build modern and responsive webpages Try Front-end

Responsive web design helps your site maintain its design integrity on a variety of screen sizes, but how does it affect your typography? With this practical book, graphic designers, web designers, and front-end developers alike will learn the nuts and bolts of how to get the best appearance from type without sacrificing performance on any device.

$ Check price
24.9924.99Amazon 4.5 logo(3+ reviews)

More Front-end resources

Ad