Benchmark: window.getComputedStyle vs. className3

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), null); }
className
var i = 3000; while (i--) { chekele('foo'); } function chekele(element) { return document.getElementById(element).className.indexOf('hide') === -1; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getComputedStyle
className

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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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 and explore what's being tested on MeasureThat.net.

**Benchmark Definition**

The provided benchmark definition is comparing two approaches to check if an element has a specific class:

1. `window.getComputedStyle(document.getElementById(element), null).className.indexOf('hide') === -1`
2. `document.getElementById(element).className.indexOf('hide') === -1`

**Options Being Compared**

These two options are being compared for their performance and accuracy.

**Pros and Cons of Each Approach:**

1. **`window.getComputedStyle` approach:**
	* Pros:
		+ More accurate, as it returns the computed style values from the element's CSS.
		+ Can be useful in cases where you need to access specific styles that are not defined on the element itself (e.g., inline styles).
	* Cons:
		+ Slower than the `className` approach, due to the additional DOM query and style computation overhead.
		+ Requires a valid CSS declaration for the `hide` class on the element's parent or ancestor.
2. **`className` approach:**
	* Pros:
		+ Faster, as it only requires a single DOM query and string search.
		+ More lightweight, as it doesn't involve style computation or accessing computed styles.
	* Cons:
		+ Less accurate, as it relies on the `indexOf()` method, which may return incorrect results for certain character sets or encoding.

**Library and Purpose**

The `document.getElementById` function is a built-in DOM API that returns an element object based on its ID. In this benchmark, it's used to retrieve the element with the specified ID (`'foo'`).

**Special JS Feature/Syntax**

There doesn't seem to be any special JavaScript features or syntax being tested in this benchmark.

**Other Alternatives**

If you want to improve the accuracy of the `className` approach, you could use a more robust string search algorithm, such as `includes()` (introduced in ECMAScript 2019). However, even with `includes()`, there's still no guarantee that the check will be accurate for all cases.

Keep in mind that microbenchmarks like this one are typically used to compare performance between different approaches or implementations. They might not cover all edge cases or scenarios, but they can provide valuable insights into which approach is faster and more efficient for a specific use case.

In summary, MeasureThat.net's benchmark is testing two approaches to check if an element has a specific class: `window.getComputedStyle` versus `className`. While the `getComputedStyle` approach provides more accuracy, it's slower due to additional DOM queries and style computation. The `className` approach is faster but less accurate, relying on string search.

Related benchmarks:

window.getComputedStyle vs. className3 (version: 0)

Comparing performance of: getComputedStyle vs className

Created: 4 years ago by: Guest

Jump to the latest result

getComputedStyle

className

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):