Benchmark: getAttribute vs. classList

HTML Preparation code:

<div id="foo" data-name="bar"></div>

Tests:

classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { return element.classList[0]; }
getAttribute
var element = document.getElementById("foo"); var i = 1000; while (i--) { return element.getAttribute("data-name"); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
classList
getAttribute

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 provided benchmark and explain what's being tested, compared, and its pros/cons.

**Benchmark Overview**

The benchmark is designed to compare two approaches for accessing class names in HTML elements: `classList` and `getAttribute`. The test cases are written as JavaScript functions that return the first class name of an element with a specific ID.

**What's Being Tested?**

* Two methods for accessing class names:
	+ `classList`: An array-like object property that provides access to all classes of an element.
	+ `getAttribute`: A method that returns the value of a named attribute, including its class.
* The performance difference between these two approaches.

**Options Compared**

The benchmark compares the execution speed of two options:

1. **`classList`**: Accessing the first class name using the `classList` property.
2. **`getAttribute` with `data-name` attribute**: Accessing the first class name using the `getAttribute` method with a named attribute (`data-name`) that contains the class value.

**Pros and Cons of Each Approach**

1. **`classList`**:
	* Pros:
		+ More JavaScript-friendly and straightforward.
		+ Provides access to all classes, not just the first one.
	* Cons:
		+ May be slower due to the overhead of iterating over the class list.
2. **`getAttribute` with `data-name` attribute**:
	* Pros:
		+ Can be faster for single-class elements, as it directly accesses the attribute value.
	* Cons:
		+ Requires a named attribute (`data-name`) that contains the class value, which might not always be available or up-to-date.

**Library and Special JS Features**

There is no specific library being used in this benchmark. However, the `classList` property is a built-in feature of JavaScript, introduced in ECMAScript 2015 (ES6).

**Other Considerations**

The benchmark assumes that the HTML element with the ID "foo" has only one class name set.

**Alternatives**

Some alternative approaches for accessing class names include:

1. **`document.querySelector`**: A method that returns an HTML element based on a CSS selector, including classes.
2. **`getElementsByClassName`**: A method that returns a NodeList of elements with the specified class name(s).
3. **Using CSS attributes**: Some browsers allow setting CSS attribute values using JavaScript. For example, `element.setAttribute('class', 'my-class');`.

These alternatives might offer different performance characteristics and trade-offs depending on the specific use case.

Overall, this benchmark provides a useful comparison of two approaches for accessing class names in HTML elements, highlighting the importance of considering performance and maintainability when writing JavaScript code.

Related benchmarks:

getAttribute vs. classList (version: 0)

Comparing performance of: classList vs getAttribute

Created: 6 years ago by: Guest

Jump to the latest result

classList

getAttribute

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):