Various ways of selecting elements from DOM in JavaScript

Published June 29, 2020

by Danica Tanjutco on Unsplash

Photo byDanica Tanjutcoon Unsplash

There are various ways you can select DOM (Document Object Model) elements in JavaScript:

are some of the commonly used methods.

document.querySelector()

The document.querySelector() method is used to select the first matching element using the CSS selectors.

Consider this html,

<div>
  <h1 class="myBigHeader">Hello EveryBody</h1>
  <div></div>
</div>

You can select the h1 tag using the myBigHeader CSS class name.

const header = document.querySelector(".myBigHeader"); // h1 tag selected

You have to put a dot . in front of the class name to access it.

🎲 NOTE: By using CSS selectors, You can also combine the tag names with the class names for more specificity.

const header = document.querySelector("div .myBigHeader"); // h1 tag selected but more specific

document.querySelectorAll()

The document.querySelectorAll() method is used to select all elements which have the same CSS selectors.

Consider this html,

<div>
  <h1 class="header">My Big Header</h1>
  <h3 class="header">Another Header</h3>
</div>

Let's select both the h1 and h3 tags.

// both h1 and h3 tags selected
const headers = document.querySelectorAll(".header");

// returns an array-like object called NodeList

document.getElementsByTagName()

The document.getElementsByTagName() method is used to select elements using the tag names only.

Consider this html,

<div>
  <h1 class="header">My Big Header</h1>
  <h3 class="header">Another Header</h3>
  <h1 class="header">My Second Big Header</h1>
</div>

Let's select the h1 tag.

const h1Header = document.getElementsByTagName("h1"); // all the h1 tags selected
// returns an array like object called HTMLCollection.

🎲 NOTE: You can't use the CSS class names here, only tag names are allowed.

document.getElementById()

The document.getElementById() method is used to select an element using the id attribute present in the html element.

Since id attributes names are unique across the HTML document, only one element is returned.

Conside this html,

<div>
  <p id="myUniqueParagraph">This is a pragragraph tag</p>
  <div></div>
</div>

Let's select the paragraph tag using the id attribute.

// paragraph tag is selected using the id attribute
const paragraph = document.getElementById("myUniqueParagraph");

// only the paragraph tag is returned

document.getElementsByClassName()

The document.getElementsByClassName method is used to select the html elements using the css classnames.

consider this html,

<div>
  <h1 class="header">My Big Header</h1>
  <h2 class="header">My Another Big Header</h2>
</div>

We can select all our header tags.

// all tags with header class names are selected
const headers = document.getElementsByClassName("header");

// returns an array like object called HTMLCollection

🎲 NOTE: We don't need to put a dot . in front of the class name in this method like we did in document.querySelector() and document.querySelectorAll() methods.

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