Benchmark: className vs. setAttribute vs. classList

HTML Preparation code:

<div id="foo"></div>

Tests:

className
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.className = "bar"; }
setAttribute
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.setAttribute("class", "bar"); }
classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.classList.add("bar"); }
Add className
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.className += "bar"; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
className
setAttribute
classList
Add 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.

I'll break down the provided benchmark and explain what's being tested, compared options, pros and cons, library usage, special JS features or syntax (if applicable), and alternative approaches.

**Benchmark Definition**

The provided JSON represents a benchmark definition for "className vs. setAttribute vs. classList". This benchmark compares three different ways to set a CSS class on an HTML element:

1. `className`
2. `setAttribute` with a value of "class"
3. `classList.add`

**Options Compared**

The three options are compared in the following individual test cases:

* **`className`**: Sets the CSS class directly on the element using the dot notation.
* **`setAttribute`**: Sets an attribute named "class" and assigns a string value to it, which then sets the CSS class.
* **`classList.add`**: Adds a new CSS class to the element's class list.

**Pros and Cons**

Here are some pros and cons of each approach:

* `className`:
	+ Pros: Simple and efficient way to set a CSS class.
	+ Cons: Can be prone to typos if not used carefully (e.g., "bar" instead of "Bar").
* `setAttribute`:
	+ Pros: Allows for more control over the attribute's value and usage.
	+ Cons: May lead to unnecessary attribute creation, which can have performance implications.
* `classList.add`:
	+ Pros: More modern and efficient way to manage CSS classes, as it avoids creating unnecessary attributes.
	+ Cons: Requires JavaScript runtime support (modern browsers).

**Library Usage**

None of the test cases explicitly use a library. However, it's worth noting that the `classList` API is supported by most modern browsers, which makes it a viable option for setting CSS classes.

**Special JS Features or Syntax**

The benchmark uses a simple JavaScript loop (`while (i--)`) to execute the code multiple times. This allows for timing measurements and comparisons between the different approaches.

**Alternative Approaches**

Some alternative ways to set a CSS class include:

* Using a string interpolation method, such as `element.classList.add(`${class}`)`.
* Using a library like jQuery or Lodash to manipulate the element's class list.
* Using a CSS-in-JS solution like Emotion or styled-components.

These alternatives may offer additional benefits, such as improved performance, easier maintenance, or more flexible styling options. However, they also introduce new dependencies and potential performance overheads.

Related benchmarks:

className vs. setAttribute vs. classList (version: 0)

Comparing performance of: className vs setAttribute vs classList vs Add className

Created: 8 years ago by: Guest

Jump to the latest result

className

setAttribute

classList

Add 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):