Benchmark: Test querySelector computed style

HTML Preparation code:

<li /><li /><li id='test' /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li /><li />

Tests:

getComputedStyle
const el = document.getElementById('test'); for (let i = 0; i < 3000; i++) window.getComputedStyle(el)
query selector
for (let i = 0; i < 3000; i++) document.querySelector('li:nth-child(5)')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getComputedStyle
query selector

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 definition and test cases to understand what is being tested.

**Benchmark Definition**

MeasureThat.net provides a website for users to create and run JavaScript microbenchmarks. The benchmark definition is a JSON object that specifies how to prepare the script, HTML, and any libraries needed for the benchmark.

In this case, the `Script Preparation Code` is empty, which means no special setup or imports are required. However, it's essential to note that some tests might require specific library imports or function calls to run correctly.

The `Html Preparation Code` defines a simple HTML structure with an `id="test"` element inside a list (`<li>`) repeated multiple times. This is used as the target element for testing the `querySelector` and `getComputedStyle` functions.

**Test Cases**

There are two individual test cases:

1. **getComputedStyle**: This test repeatedly calls `window.getComputedStyle(el)` on an element retrieved using `document.getElementById('test')`. The loop runs 3000 times, which is likely used to warm up the browser's cache and simulate a heavy workload.
2. **query selector**: This test also uses the same HTML structure but queries for an element using `document.querySelector('li:nth-child(5)')`, which selects the fifth child element of the first list item.

**Options Compared**

The two tests compare the performance of two different DOM manipulation approaches:

1. **getComputedStyle**: Uses the `window.getComputedStyle` function to retrieve the computed style of an element.
2. **query selector**: Uses the `document.querySelector` function to select elements based on a CSS query.

**Pros and Cons**

Here are some pros and cons of each approach:

* **getComputedStyle**:
	+ Pros: Can be faster for retrieving styles, as it bypasses DOM traversal.
	+ Cons: May not work correctly in older browsers or when the element is removed from the DOM.
	+ Additional overhead due to function call and caching.
* **query selector**:
	+ Pros: Works consistently across modern browsers and can be used for more complex queries.
	+ Cons: Can be slower than `getComputedStyle` due to DOM traversal, especially for large datasets.

**Libraries and Special Features**

In this case, there are no specific library imports mentioned in the benchmark definition. However, it's worth noting that MeasureThat.net might use some internal libraries or utilities to run the benchmarks and provide the results.

If you're interested in exploring other alternatives, here are a few options:

* **Benchmarking frameworks**: There are several benchmarking frameworks available for JavaScript, such as Benchmark.js, Microbench.js, or js-benchmark. These frameworks often provide more features and flexibility than MeasureThat.net.
* **Browser-specific benchmarks**: Each browser vendor provides its own set of benchmarks to test the performance of their browser. For example, Chrome's benchmarking suite includes tests for web page loading, rendering, and other performance-related metrics.

Overall, MeasureThat.net provides a convenient way to compare the performance of different DOM manipulation approaches, but if you need more control or flexibility, exploring other benchmarking options might be beneficial.

Related benchmarks:

Test querySelector computed style (version: 0)

Comparing performance of: getComputedStyle vs query selector

Created: 2 years ago by: Guest

Jump to the latest result

getComputedStyle

query selector

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):