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Table of contents
1.
Introduction
2.
What is querySelectorAll
2.1.
When to Use It
2.2.
Syntax and Parameters
3.
Example Program
3.1.
HTML
3.2.
Detailed Method Explanation with Working Example
4.
Table: Use Cases for querySelectorAll
5.
Frequently Asked Questions
5.1.
What's the difference between querySelector and querySelectorAll?
5.2.
What does querySelector all do?
5.3.
How to get all DOM elements in JavaScript?
5.4.
How to select all id in JavaScript?
6.
Conclusion
Last Updated: Mar 27, 2024
Easy

Queryselectorall

Author Rinki Deka
0 upvote

Introduction

In web development, working with the Document Object Model (DOM) is essential. JavaScript offers several methods for selecting and manipulating DOM elements, with querySelectorAll standing out for its versatility. This method allows developers to efficiently target and manipulate multiple elements within the DOM.

querySelectorAll

This article will dive deep into the querySelectorAll method, providing a thorough understanding along with practical examples.

What is querySelectorAll

querySelectorAll is a method available on document objects in JavaScript that returns a static NodeList representing a list of the document's elements that match the specified group of selectors.

When to Use It

querySelectorAll is particularly useful when you need to select multiple elements that share the same CSS selector. It's a go-to choice when dealing with classes, complex CSS selectors, or when you need to apply changes to a collection of elements in the DOM.

Syntax and Parameters

The syntax for querySelectorAll is as follows:

document.querySelectorAll(selectorString);

selectorString: A string representing the selector to match.

Example

Let's say we have a set of paragraphs we want to select with the class .highlight.

<p class="highlight">First highlighted item</p>
<p class="highlight">Second highlighted item</p>
<p>Not highlighted</p>

Using querySelectorAll, we can select these paragraphs as follows:

const highlightedItems = document.querySelectorAll('.highlight');

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Example Program

Here's a  example that uses querySelectorAll to change the background color of all elements with the class .highlight.

  • HTML

HTML

<!DOCTYPE html>

<html lang="en">

<head>

<meta charset="UTF-8">

<meta name="viewport" content="width=device-width, initial-scale=1.0">

<title>querySelectorAll Example</title>

<style>

.highlight {

padding: 5px;

border: 1px solid #ccc;

}

</style>

</head>

<body>

<p class="highlight">First highlighted item</p>

<p class="highlight">Second highlighted item</p>

<p>Not highlighted</p>

<script>

// Select all elements with the class 'highlight'

const highlightedItems = document.querySelectorAll('.highlight');


// Iterate over the NodeList and change the background color

highlightedItems.forEach(item => {

item.style.backgroundColor = 'yellow';

});

</script>


</body>

</html>

Output 

Output

If you copy and paste the above code into an HTML file and open it in a web browser, you'll see that only the paragraphs with the class .highlight have their background color changed to yellow.

Detailed Method Explanation with Working Example

The querySelectorAll method returns a NodeList. It's important to note that a NodeList is not an Array, but it can be converted to an Array using Array.from() if needed. The NodeList is static, meaning it won't update if the DOM changes later on.

In the above example, we used the forEach method to iterate over the NodeList. This method is available on NodeLists in modern browsers and allows us to execute a function on each item in the list.

Table: Use Cases for querySelectorAll

Use Case Example
Selecting elements with a specific class document.querySelectorAll('.my-class')
Selecting elements with a specific ID  document.querySelectorAll('#my-id')
Selecting elements with a specific attribute document.querySelectorAll('[data-my-attribute]')
Combining selectors  document.querySelectorAll('div.my-class, span.my-class')

Frequently Asked Questions

What's the difference between querySelector and querySelectorAll?

querySelector returns the first element that matches the specified selectors, whereas querySelectorAll returns all matching elements as a NodeList.

What does querySelector all do?

querySelectorAll is a JavaScript method used to select and return a NodeList of all elements in the document that match a specified CSS selector. It allows for a more complex and specific selection of DOM elements for manipulation or data retrieval.

How to get all DOM elements in JavaScript?

To get all DOM elements in JavaScript, you can use the document.getElementsByTagName('*') method. This returns a live HTMLCollection of every element in the document, allowing you to iterate over and manipulate each element as needed.

How to select all id in JavaScript?

In JavaScript, you can use document.querySelectorAll('[id]') to select all elements with an ID. This method returns a NodeList of all elements that have an ID attribute, allowing you to iterate through and manipulate these elements as needed.

Conclusion

querySelectorAll is a powerful tool in the JavaScript arsenal for DOM manipulation. It provides a concise and flexible way to select multiple elements and perform actions on them. Understanding how to effectively use querySelectorAll can streamline your code and make your DOM manipulations more efficient. With the examples and explanations provided, you should now have a solid grasp of how to implement querySelectorAll in your projects, ensuring your code is both functional and elegant.

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