Benchmark: getElementsByClassName VS querySelector test1

HTML Preparation code:

<div class="example container"></div>
<div class="example container"></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example"></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example"></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example "></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example container"></div>
<div class="example"></div>
<div class="example container"></div>
<div class="example container"></div>

Tests:

The method getElementsByClassName()
document.getElementsByClassName("container");
The method querySelectorAll()
document.querySelector('[class*="container"]');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
The method getElementsByClassName()
The method querySelectorAll()

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark.

**Benchmark Definition**

The benchmark compares two approaches to select HTML elements:

1. `document.getElementsByClassName("container")`
2. `document.querySelector('[class*="container"]')`

These two methods are used to retrieve all elements with a specific class (`"container"`). The first method uses a traditional array-based approach, while the second method uses CSS selectors.

**Options Compared**

The benchmark compares the performance of these two methods:

1. **`getElementsByClassName()`**: This method returns an array-like object containing all elements that match the specified class name.
2. **`querySelectorAll()`**: This method returns a NodeList (a live HTML collection) containing all elements that match the specified CSS selector.

**Pros and Cons**

### `getElementsByClassName()`

Pros:

* Simple to understand and implement
* Well-supported by most browsers

Cons:

* Can be slower than using CSS selectors, especially for complex class names
* Returns an array-like object, which may not be as efficient as a NodeList in some cases

### `querySelectorAll()` (CSS Selectors)

Pros:

* Can be faster than using `getElementsByClassName()` for complex class names or element selection
* Allows for more flexible and expressive CSS selectors

Cons:

* May require more effort to understand and implement, especially for beginners
* Not all browsers support CSS selectors, although most modern browsers do.

**Library Used**

There is no explicit library used in this benchmark. However, both methods rely on the browser's built-in DOM (Document Object Model) APIs.

**Special JS Feature or Syntax**

This benchmark does not use any special JavaScript features or syntax, such as async/await, promises, or modern ES6+ features like let and const declarations.

**Other Alternatives**

If you want to compare these methods with other alternatives, here are some options:

1. **`querySelector()`**: This method returns a single element that matches the specified CSS selector.
2. **`getElementsByClassName()` variant**: Some browsers provide an alternative `getElementsByName()` method for selecting elements by name.
3. **`CSSOM QueryList` API**: This API provides more advanced features for querying and manipulating CSS selections, but is less widely supported than DOM APIs.

Keep in mind that the choice of method depends on your specific use case and requirements. The benchmark provided by MeasureThat.net helps to compare the performance of these two common approaches, allowing you to make an informed decision about which one to use in your own projects.

Related benchmarks:

getElementsByClassName VS querySelector test1 (version: 0)

Comparing performance of: The method getElementsByClassName() vs The method querySelectorAll()

Created: 3 years ago by: Guest

Jump to the latest result

The method getElementsByClassName()

The method querySelectorAll()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):