Benchmark: window.getComputedStyle vs. classList.contains

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).getPropertyValue("display").indexOf('none') === -1; }
className
var i = 3000; while (i--) { chekele('foo'); } function chekele(element) { return document.getElementById(element).classList.contains('hide'); }

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:

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches to check if an HTML element is hidden:

1. `window.getComputedStyle` (test case 1)
2. `classList.contains` (test case 2)

**Options Compared**

In this benchmark, we have two options:

* **Option 1: Using `window.getComputedStyle`**
	+ This method retrieves the computed style of an element and checks if the "display" property is set to "none".
	+ The idea is that if the display property is set to none, the element is considered hidden.
	+ However, this approach has some limitations:
		- It can be slow because it involves getting the CSS styles of the element, which might involve more network requests or computations.
		- It may not work as expected in all cases (e.g., if the `display` property is set to "none" but there's another style that sets it back to a non-hidden value).
* **Option 2: Using `classList.contains('hide')`**
	+ This method checks if the `hide` class is present on the element.
	+ The idea is that if the element has the `hide` class, it's considered hidden.
	+ However, this approach also has some limitations:
		- It relies on the presence of a specific class (`hide`) which might not be guaranteed or consistent across all browsers and use cases.

**Pros and Cons**

* **Option 1 (window.getComputedStyle)**: Pros - more robust, as it checks the actual CSS styles. Cons - slower, may have edge cases.
* **Option 2 (classList.contains('hide'))**: Pros - faster, simpler to implement. Cons - relies on a specific class (`hide`), may not work consistently.

**Other Considerations**

* The benchmark uses JavaScript and HTML/CSS to test these two approaches.
* It's worth noting that using `window.getComputedStyle` can be slower because it involves more computations and potentially more network requests.
* The presence of the `hide` class is assumed, which might not always be the case.

**Library or Special JS Feature**

There is no specific library used in this benchmark. However, it does use a JavaScript feature called `classList` (short for "class list"), which was introduced in ECMAScript 2015 (ES6). The `classList.contains()` method is part of the DOM API and allows you to check if an element has a specific class.

**Other Alternatives**

If you want to test similar approaches, you could consider:

* Using CSS classes instead of JavaScript libraries.
* Implementing your own custom solution for checking hidden elements (e.g., using a flag or a separate element).
* Testing other CSS properties that might indicate hiding (e.g., `opacity`, `visibility`, etc.).

Related benchmarks:

window.getComputedStyle vs. classList.contains (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):