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className vs. setAttribute vs. classListasdfa
(version: 0)
Benchmark.js
Comparing performance of:
className vs setAttribute vs classList
Created:
2 years ago
by:
Guest
Go to the latest result
HTML Preparation code:
<div id="foo"></div>
Tests:
className
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.className = "bar foo shit"; }
setAttribute
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.setAttribute("class", "bar foo shit"); }
classList
var element = document.getElementById("foo"); var i = 1000; while (i--) { element.classList.add("bar", "foo", "shit"); }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
className
setAttribute
classList
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36
Browser/OS:
Chrome 119 on Mac OS X 10.15.7
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=488190" width="100%" height="500px"></iframe>
className
17K/s
setAttribute
10K/s
classList
2K/s
View exact numbers
Test name
Executions per second
✓
className
16,664 Ops/sec
setAttribute
10,167 Ops/sec
classList
2,354 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Benchmark Overview** The provided benchmark measures the performance difference between three approaches to add or modify CSS classes on an HTML element: 1. `className` 2. `setAttribute` (specifically, setting the `class` attribute) 3. `classList` These methods are used to dynamically update the class names of an HTML element. **Options Comparison** The benchmark compares these three approaches for two reasons: * **Performance**: How quickly can each approach be executed? The goal is to determine which method has the best performance in terms of time. * **Readability and Maintainability**: How easy is it to understand and maintain the code that uses each approach? **Pros and Cons** 1. **className** * Pros: Simple, readable, and well-supported by modern browsers. * Cons: May not work as expected in older browsers or with certain CSS rules (e.g., `!important`). 2. **setAttribute** * Pros: Works consistently across all browsers, including legacy ones. * Cons: Can be less readable than other methods, especially when dealing with multiple classes. 3. **classList** * Pros: Modern and concise way to manage class names, widely supported by modern browsers. * Cons: May not work in older browsers or with specific CSS rules. **Library Usage** None of the provided benchmark cases use any external libraries. However, it's worth noting that `classList` is a part of the ECMAScript standard (ES6+), making it a more modern and consistent approach. **Special JS Features or Syntax** The benchmark uses ES6 features, specifically: * `const` keyword for variable declarations. * Template literals (`\r\n`) for string interpolation. These features are widely supported by modern browsers but may not be compatible with older browsers. **Other Alternatives** Alternative approaches to add or modify CSS classes on an HTML element include: * **DOM manipulation**: Directly modifying the `className` attribute using a loop, like in the `setAttribute` case. * **CSS classes with inline styles**: Using the `style` attribute to set CSS classes and their properties directly on the element. * **MutationObserver**: Observing changes to the DOM and reacting to class name changes. Each of these alternatives has its pros and cons, and may be suitable for specific use cases or performance-critical code.
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