Benchmark: Attribute Selector vs Class Selector vs ID Selector

HTML Preparation code:

<div class="hello" id="hello" data="hello">Hello</div>

Tests:

Class
document.querySelector('.hello');
ID
document.querySelector('#hello');
Attribute
document.querySelector('[data="hello"]');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Class
ID
Attribute

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'll break down the provided JSON and explain what's being tested, the different approaches compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark definition is a simple JavaScript code snippet that uses the `document.querySelector()` method to select an HTML element based on its class, ID, or attribute value. The goal is to compare the performance of these three approaches:

1. **Class Selector**: `document.querySelector('.hello');`
2. **ID Selector**: `document.querySelector('#hello');`
3. **Attribute Selector**: `document.querySelector('[data="hello"]');`

**Options Compared**

The benchmark compares the execution time of each approach on different browsers and devices.

* **Browsers**: Chrome 122 (on Desktop)
* **Devices**: Desktop platforms
* **Operating Systems**: Windows

**Pros and Cons of Different Approaches:**

1. **Class Selector**:
	* Pros:
		+ Fast and efficient, as it only requires a single CSS selector.
		+ Can be used for both static and dynamic elements.
	* Cons:
		+ May not work well if the class is dynamically added or removed.
2. **ID Selector**:
	* Pros:
		+ Works reliably, even when the element has multiple IDs (e.g., `id="hello-123"`).
		+ Can be used for both static and dynamic elements.
	* Cons:
		+ May slow down performance if there are many ID-selectable elements on the page.
3. **Attribute Selector**:
	* Pros:
		+ Works even when the element has multiple attributes (e.g., `[data="hello"]`).
		+ Can be used for both static and dynamic elements.
	* Cons:
		+ May slow down performance if there are many attribute-selectable elements on the page.

**Library Used**

In this benchmark, no libraries are explicitly mentioned. However, `document.querySelector()` is a part of the DOM (Document Object Model) API, which is a built-in JavaScript API for working with HTML and XML documents.

**Special JS Features or Syntax**

None mentioned.

**Other Considerations**

When comparing these approaches, it's essential to consider the following:

* **CSS Selectors**: The performance difference between class selectors, ID selectors, and attribute selectors depends on the CSS selector engine used by the browser. Modern browsers like Chrome use a combination of CSS parser and selector algorithms to optimize performance.
* **Element Count**: If there are many elements with these attributes or IDs, the performance difference may be less noticeable due to the overhead of DOM manipulation.
* **Browser Updates**: Benchmark results may vary across different browser versions and architectures.

**Alternatives**

If you want to test similar approaches, consider using benchmarks like:

* `element-from-viewport` (for selecting elements based on their position in the viewport)
* `css-selector-performance` (for comparing CSS selector performance)

Keep in mind that these alternatives might have slightly different use cases or requirements. MeasureThat.net's benchmark is well-suited for testing class selectors, ID selectors, and attribute selectors in a general-purpose scenario.

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36

Browser/OS: Chrome 122 on Windows

View result in a separate tab

Test name	Executions per second
Class	8315933.0 Ops/sec
ID	6018359.5 Ops/sec
Attribute	5320836.0 Ops/sec

Related benchmarks:

Attribute Selector vs Class Selector vs ID Selector (version: 0)

Comparing performance of: Class vs ID vs Attribute

Created: 6 months ago by: Guest

Jump to the latest result

Class

ID

Attribute

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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