Benchmark: className vs classList

HTML Preparation code:

<style>
  .redText
  {
    color: red;
  }
  
  .redBorder
  {
    border: 1px solid red;
  }
</style>

<div id="testDiv">Sample div</div>

Tests:

className
var div = document.getElementById('testDiv'); div.className += 'redText'; div.className += 'redBorder';
classList
var div = document.getElementById('testDiv'); div.classList.add('redText'); div.classList.add('redBorder');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
className
classList

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):

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Let's break down what is being tested in the provided JSON and explain the options compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark defines two test cases: `className` and `classList`. Both tests aim to measure the performance of adding classes to an HTML element using either the `className` property or the `classList` API.

**Options Compared**

1. **`className` Property**: This approach uses the `className` property to add classes to the element. The `className` property is a string that contains multiple class names separated by spaces.
2. **`classList` API**: This approach uses the `classList` API, which is a more modern and efficient way of adding classes to an element. The `classList` API is a collection-like object that allows you to add, remove, or toggle classes on an element.

**Pros and Cons**

* **`className` Property**:
	+ Pros: Widely supported across different browsers and versions.
	+ Cons: Can be slower and more memory-intensive due to the need to concatenate class names into a single string.
	+ Pros: More readable and maintainable code, as individual classes can be easily added or removed separately.
	+ Cons: May lead to performance issues if the class name strings are very long or concatenated multiple times.
* **`classList` API**:
	+ Pros: More efficient and modern, reducing memory usage and improving performance.
	+ Cons: Less widely supported across different browsers and versions, particularly older ones.

**Library Used**

In this benchmark, no libraries are explicitly mentioned. However, the `classList` API is a part of the Web APIs, which are built-in to modern browsers.

**Special JS Feature or Syntax**

There are no special JavaScript features or syntaxes used in this benchmark. The code only uses standard JavaScript and HTML/CSS elements.

**Other Considerations**

* **Browser Support**: Both approaches have varying degrees of browser support. The `className` property is widely supported, while the `classList` API may have issues in older browsers.
* **Performance Impact**: The performance impact of using either approach depends on the specific use case and implementation. However, the `classList` API is generally considered more efficient due to its optimized implementation.

**Alternatives**

If you're interested in exploring alternative approaches or testing different browsers, here are a few options:

1. **Other class addition methods**: You could test adding classes using other methods, such as `innerHTML`, `style`, or using JavaScript libraries like jQuery.
2. **Different browsers**: Test the performance of both approaches across multiple browsers to identify potential issues and differences in support.
3. **Class name length and concatenation**: Experiment with varying class name lengths and concatenations to see how they affect performance, especially when using the `className` property.

By testing these alternatives, you can gain a better understanding of the trade-offs involved in choosing between different approaches for adding classes to HTML elements.

Related benchmarks:

className vs classList (version: 0)

Comparing performance of: className vs classList

Created: 9 years ago by: Guest

Jump to the latest result

className

classList

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):