Benchmark: window.style vs. getBoundingClientRect

HTML Preparation code:

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

Tests:

style
var i = 5000; while (i--) { checkDisplay('foo'); } function checkDisplay(id) { let element = document.getElementById(id); return element.style.width; }
getBoundingClientRect
var i = 5000; while (i--) { checkDisplay('foo'); } function checkDisplay(id) { return document.getElementById(id).getBoundingClientRect().width === 0; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
style
getBoundingClientRect

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the provided benchmark and explain what is tested, compared, and some pros and cons of each approach.

**Benchmark Definition**

The benchmark definition represents two test cases: `style` and `getBoundingClientRect`. Both tests aim to compare the performance of getting the width property of an element using `window.style.width` versus `document.getElementById(id).getBoundingClientRect().width`.

**Script Preparation Code and Html Preparation Code**

The script preparation code is empty, which means that the benchmark doesn't perform any additional setup or initialization before running the test. However, it's essential to note that this might affect the results.

The html preparation code provides a simple `<div id="foo"></div>` element, which will be used as the target for the width measurement.

**Individual Test Cases**

There are two individual test cases:

1. **`style`**: This test case runs a while loop 5000 times, calling the `checkDisplay('foo')` function inside the loop. The function uses `window.style.width` to get the width of the element and returns its value.
2. **`getBoundingClientRect`**: This test case is similar to the first one but uses `document.getElementById(id).getBoundingClientRect().width` to get the width of the element.

**Library: `checkDisplay`**

The `checkDisplay` function is not a built-in JavaScript library, but rather a custom implementation used in both test cases. Its purpose is to measure the width of an element using either `window.style.width` or `document.getElementById(id).getBoundingClientRect().width`. This function is likely written by the benchmark creator to simplify the measurement process.

**Comparison**

The comparison between `style` and `getBoundingClientRect` test cases aims to determine which method is faster for measuring the width of an element. The results will show how many executions per second each method achieves, with higher values indicating better performance.

**Pros and Cons:**

* **`window.style.width`**:
	+ Pros: Simple, widely supported, and easy to implement.
	+ Cons: May not provide accurate results due to potential CSS styles or layout issues affecting the element's width.
* **`document.getElementById(id).getBoundingClientRect().width`**:
	+ Pros: More accurate, as it measures the element's width based on its bounding rectangle, ignoring any CSS styles or layout issues.
	+ Cons: May be slower due to additional calculations required to access and calculate the bounding rectangle.

**Special JS Feature/Syntax:**

There are no special JavaScript features or syntax used in this benchmark. However, it's essential to note that the `getBoundingClientRect` method was introduced in HTML5 and might not be supported in older browsers.

**Other Alternatives:**

If you were to create a similar benchmark, other alternatives could include:

* Using CSS classes instead of inline styles for better accuracy
* Measuring element width using `getComputedStyle()` or `window.getComputedStyle()`
* Using a library like FastDOM or Wasm.js for faster rendering and measurement

Keep in mind that the choice of approach depends on your specific use case, performance requirements, and target browsers.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/13.1.3 Safari/605.1.15

Browser/OS: Safari 13 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
style	547.0 Ops/sec
getBoundingClientRect	242.7 Ops/sec

Related benchmarks:

window.style vs. getBoundingClientRect (version: 0)

Comparing performance of: style vs getBoundingClientRect

Created: 2 years ago by: Registered User

Jump to the latest result

style

getBoundingClientRect

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):