Benchmark: window.getComputedStyle vs. inline style

HTML Preparation code:

<div id="foo" style="transform:scale(1);"></div>

Tests:

getComputedStyle
var i = 1000; while (i--) { chekele('foo'); } function chekele(id) { return window.getComputedStyle(document.getElementById(id)).transform != null; }
inline
var i = 1000; while (i--) { chekele('foo'); } function chekele(id) { return document.getElementById(id).style.transform != null; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getComputedStyle
inline

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 10 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
getComputedStyle	936.5 Ops/sec
inline	7505.0 Ops/sec

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 and explain what's being tested.

**Benchmark Definition**

The benchmark is defined in two parts:

1. The HTML preparation code creates an empty `<div>` element with an ID of "foo" and styles it to have a `transform:scale(1)` CSS rule.
2. The script preparation code is not provided, but it likely sets up some variables and functions that will be used in the benchmark.

**Individual Test Cases**

The benchmark consists of two test cases:

1. **getComputedStyle**: This test case uses the `window.getComputedStyle()` function to check if the `transform` CSS rule is present on the element with ID "foo".
2. **inline**: This test case uses the `document.getElementById(id).style.transform != null` syntax to check if the `transform` CSS rule is present on the element with ID "foo".

**What's Being Tested**

The benchmark is testing the performance difference between using `window.getComputedStyle()` and accessing the `style` property directly on an HTML element.

**Options Compared**

Two options are being compared:

1. **window.getComputedStyle()**: This function returns a CSSStyleDeclaration object that represents the computed style of the specified element.
2. **inline**: This syntax accesses the `style` property directly on an HTML element, allowing direct access to the element's CSS rules.

**Pros and Cons**

Here are some pros and cons of each approach:

* **window.getComputedStyle()**:
	+ Pros:
		- Provides a more robust way to retrieve an element's computed style, as it takes into account any applied CSS rules.
		- Can be useful for cross-browser compatibility issues.
	+ Cons:
		- May be slower than accessing the `style` property directly on an HTML element.
* **inline**:
	+ Pros:
		- Faster than using `window.getComputedStyle()`, as it avoids the need to create and return a new object.
	+ Cons:
		- May not work across all browsers, as some may not support accessing CSS rules on an HTML element.

**Library Usage**

Neither of these test cases uses any external libraries. The `getComputedStyle()` function is a built-in JavaScript method that returns the computed style of an element, while the inline syntax relies solely on the DOM API.

**Special JS Features or Syntax**

The benchmark does not use any special JavaScript features or syntax beyond what's necessary to access and manipulate HTML elements. No ES6+ features like async/await or template literals are used.

**Other Alternatives**

If you were to modify this benchmark, some alternative approaches could be explored:

* Using a more robust CSS query method, such as `element.querySelector()` or `element.matchSelector()`, which may provide better performance and cross-browser compatibility.
* Adding a third test case that uses a library like jQuery or another DOM manipulation library to access the element's style rules.
* Introducing additional HTML elements with different styles to create more variability in the benchmark.

Overall, this benchmark provides a straightforward comparison between two common ways to access an HTML element's CSS rules.

Related benchmarks:

window.getComputedStyle vs. inline style (version: 0)

Comparing performance of: getComputedStyle vs inline

Created: 2 years ago by: Guest

Jump to the latest result

getComputedStyle

inline

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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