Benchmark: window.getComputedStyle vs. getBoundingClientRect 2

HTML Preparation code:

<div id="foo"></div>

Tests:

getComputedStyle
var i = 3000; while (i--) { chekele('foo'); } function chekele(element) { return window.getComputedStyle(document.getElementById(element)); }
getBoundingClientRect
var i = 3000; while (i--) { chekele('foo'); } function chekele(element) { return document.getElementById(element).getBoundingClientRect(); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getComputedStyle
getBoundingClientRect

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser/OS: Chrome 124 on Windows

View result in a separate tab

Test name	Executions per second
getComputedStyle	1040.7 Ops/sec
getBoundingClientRect	410.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition and Preparation**

The benchmark measures the performance difference between two approaches: `window.getComputedStyle` and `getBoundingClientRect`. The benchmark preparation code consists of an HTML snippet with a single `<div>` element, which is used as the target for both measurements.

**Options Compared**

The benchmark compares the following options:

1. **`window.getComputedStyle`**: This method retrieves the CSS styles of an element using the `window` object and its built-in `getComputedStyle()` function.
2. **`getBoundingClientRect`**: This method returns the size of an element relative to the viewport, without considering its offset from the viewport.

**Pros and Cons**

* **`window.getComputedStyle`**:
	+ Pros: More flexible and accurate for retrieving styles that don't affect layout (e.g., font sizes, padding).
	+ Cons: Can be slower due to the additional DOM lookup.
* **`getBoundingClientRect`**:
	+ Pros: Faster and more suitable for measuring layout-related properties (e.g., width, height).
	+ Cons: May not provide accurate results if the element's position or size changes dynamically.

**Library Usage**

The benchmark uses the `document.getElementById()` method to retrieve the `<div>` element, which is a built-in JavaScript API.

**Special JS Feature/Syntax**

None mentioned in this specific benchmark. However, some modern browsers may use other APIs like `requestIdleCallback` for performance-critical code.

**Other Alternatives**

If you're interested in exploring alternative approaches or optimizing your own JavaScript benchmarks:

1. **`DOM manipulations`**: Measuring the performance of complex DOM mutations (e.g., appending, inserting, removing elements).
2. **`CSS calculations`**: Comparing the performance of different CSS calculation methods (e.g., `calc()`, `grid-template-areas`, etc.).
3. **`Async operations`**: Benchmarking the performance of asynchronous code using techniques like `Promise.all()` or `async/await`.
4. **`Web Workers`**: Measuring the performance benefits of using Web Workers for parallelized JavaScript execution.

Keep in mind that each benchmark should be tailored to its specific use case and goals.

Related benchmarks:

window.getComputedStyle vs. getBoundingClientRect 2 (version: 0)

Comparing performance of: getComputedStyle vs getBoundingClientRect

Created: 2 years ago by: Guest

Jump to the latest result

getComputedStyle

getBoundingClientRect

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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