Benchmark: document.getElementById+querySelectorAll

HTML Preparation code:


<div id='test'>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
</div>
<div id='test1'>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
</div>

<div id='test2'>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
  <button data-id="button" >test</button>
</div>

Tests:

getElementByID+querySelectorAll
document.getElementById('test').querySelectorAll('[data-id]');
querySelectorAll
document.querySelectorAll('#test [data-id]');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementByID+querySelectorAll
querySelectorAll

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:150.0) Gecko/20100101 Firefox/150.0

Browser/OS: Firefox 150 on Linux

View result in a separate tab

getElementByID+querySelectorAll

3.6M/s

querySelectorAll

1.1M/s

View exact numbers

Test name	Executions per second
✓ getElementByID+querySelectorAll	3,595,496 Ops/sec
querySelectorAll	1,092,292 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 is tested, compared, and analyzed in the benchmark.

**Benchmark Definition**

The benchmark is comparing two approaches to retrieve elements with the `data-id` attribute:

1. **document.getElementById('test').querySelectorAll('[data-id]')**: This method uses `getElementById` to find an element by its ID (`'test'`) and then calls `querySelectorAll` on that element, selecting all descendants with the `[data-id]` pseudo-class.
2. **document.querySelectorAll('#test [data-id]')**: This method uses `querySelectorAll` directly to select elements that match both the `#test` selector (an ID selector) and the `[data-id]` pseudo-class.

**Library and Syntax**

In both cases, no libraries or special JavaScript features are used beyond standard DOM manipulation syntax. However, it's worth noting that some browsers might have optimized these methods or added additional features since their initial implementation.

**Comparison of Options**

The two approaches differ in how they use the DOM API:

1. **document.getElementById('test').querySelectorAll('[data-id]')**:
	* Advantages:
		+ May be faster because `getElementById` is a single step instead of a multi-step process with `querySelectorAll`.
		+ Can be more efficient if the element is already cached in memory.
	* Disadvantages:
		+ Requires an additional lookup for the element ID, which might introduce overhead.
		+ May not take advantage of caching or optimization in modern browsers.
2. **document.querySelectorAll('#test [data-id]')**:
	* Advantages:
		+ Only requires a single step to select all matching elements.
		+ Can potentially benefit from browser optimizations and caching for `querySelectorAll`.
	* Disadvantages:
		+ May be slower due to the additional lookup required for the ID selector.

**Other Considerations**

1. **Browser Variability**: The benchmark results are specific to Chrome 113 on a Mac OS X system, which might not reflect performance differences in other browsers or environments.
2. **DOM Size and Complexity**: The number of elements with the `[data-id]` pseudo-class affects the performance of both methods. A larger set of elements could lead to slower execution times.
3. **Cache and Optimization**: Modern browsers often cache frequently accessed DOM nodes, which can impact the performance of these benchmark results.

**Alternatives**

If you were to explore alternative approaches or optimization strategies, consider:

1. **Using `document.querySelector` instead of `querySelectorAll`, as it returns a single element (if found) rather than a NodeList.
2. **Implementing a custom caching mechanism for frequently accessed DOM elements.
3. **Optimizing the DOM structure and layout to reduce the number of elements with the `[data-id]` pseudo-class.

Keep in mind that these alternatives would likely require additional modifications to your benchmark code, as they involve specific browser features or optimizations not directly related to the original test cases.

document.getElementById+querySelectorAll (version: 0)

Comparing performance of: `getElementByID+querySelectorAll vs querySelectorAll`

Created: 3 years ago by: Guest

Go to the latest result

getElementByID+querySelectorAll

querySelectorAll

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

document.getElementById+querySelectorAll (version: 0)

Comparing performance of: getElementByID+querySelectorAll vs querySelectorAll

Created: 3 years ago by: Guest

Go to the latest result

getElementByID+querySelectorAll

querySelectorAll

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: `getElementByID+querySelectorAll vs querySelectorAll`