Benchmark: querySelector(), document vs nested element

HTML Preparation code:

<header>
  <p>header</p>
</header>
<section>
    <div>
        <p class="text">Text</p>
    </div>
</section>
<footer>
  <p>footer</p>
</footer>

Script Preparation code:

var section = document.querySelector('section');

Tests:

document
var text1 = document.querySelector('.text')
nested element
var text2 = section.querySelector('.text')

Historical Performance Data aggregated from 14 community runs

Desktop Results:

Chrome 14 runs

nested element

15.4M/s

document

7.3M/s

Fastest: nested element (2.1x faster)

View exact numbers

✓ nested element: 15,408,390 ops/sec
• document: 7,343,755 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
document
nested element

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Safari/537.36 OPR/125.0.0.0

Browser/OS: Opera 125 on Windows

View result in a separate tab

nested element

38.0M/s

document

16.0M/s

View exact numbers

Test name	Executions per second
✓ nested element	37,991,620 Ops/sec
document	16,047,744 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON and explain what's being tested on MeasureThat.net.

**Benchmark Definition**

The benchmark definition is a set of parameters that describe how to prepare the test environment and run the test. In this case, there are two benchmark definitions:

1. "querySelector(), document vs nested element"
2. "var text1 = document.querySelector('.text') "
3. "var text2 = section.querySelector('.text')"
4. "var text3 = document.querySelector('.text')"
5. "var text4 = section.querySelector('.text')"

These benchmarks test the performance of different approaches to selecting elements using the `querySelector()` method in JavaScript.

**Options Compared**

The two main options being compared are:

1. **Direct access**: Using `document` as a selector, which means accessing the root element directly.
2. **Nested access**: Using a nested element (`section`) as a selector, which means traversing the DOM tree to reach the target element.

**Pros and Cons of Each Approach**

* Direct Access (using `document`):
	+ Pros:
		- Generally faster since it involves less DOM traversal.
		- Can be more efficient for simple selectors.
	+ Cons:
		- May lead to slower performance when dealing with complex or deeply nested elements.
		- Increases the risk of errors if the wrong element is accessed accidentally.
* Nested Access (using a nested element (`section`)):
	+ Pros:
		- Can be more robust and accurate, especially for complex or dynamically generated HTML structures.
		- Reduces the risk of errors when dealing with incorrect or missing elements.
	+ Cons:
		- Typically slower due to increased DOM traversal.

**Library**

In this benchmark, there is no explicit library mentioned. However, it's likely that the `document` object and its methods are part of the built-in JavaScript API.

**Special JS Feature/Syntax**

There isn't any special JavaScript feature or syntax explicitly used in these benchmarks. The tests only rely on standard JavaScript and DOM manipulation techniques.

**Other Alternatives**

If you're interested in exploring alternative approaches or optimizations, here are a few options:

* Using a library like **QuerySelector** (a polyfill for the `querySelector` method) to improve compatibility across browsers.
* Utilizing modern JavaScript features like **CSS Selectors** or **Template Literals** to simplify and optimize your code.
* Considering other query methods like **getElementsByClassName()` or **getElementsByTagName()`, although these may have different performance characteristics.

Keep in mind that the specific alternatives will depend on your project requirements, target browsers, and personal preferences.

querySelector(), document vs nested element (version: 0) Benchmark.js

Comparing performance of: `document vs nested element`

Created: 5 years ago by: Guest

Go to the latest result

document

nested element

Historical Performance Data aggregated from 14 community runs

Desktop Results:

Chrome 14 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

querySelector(), document vs nested element (version: 0) Benchmark.js

Comparing performance of: document vs nested element

Created: 5 years ago by: Guest

Go to the latest result

document

nested element

Historical Performance Data aggregated from 14 community runs

Desktop Results:

Chrome 14 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `document vs nested element`