Benchmark: Get elements by class: jQuery vs querySelectorAll vs getElementsByClassName

HTML Preparation code:

<ul id="theList">
  <li class="odd">Item 1</li>    
  <li class="even">Item 2</li>    
  <li class="odd">Item 3</li>    
  <li class="even">Item 4</li>    
  <li class="odd">Item 5</li>    
  <li class="even">Item 6</li>    
  <li class="odd">Item 7</li>    
  <li class="even">Item 8</li>    
  <li class="odd">Item 9</li>    
  <li class="even">Item 10</li>    
  <li class="odd">Item 11</li>    
  <li class="even">Item 12</li>    
  <li class="odd">Item 13</li>    
  <li class="even">Item 14</li>    
  <li class="odd">Item 15</li>    
  <li class="even">Item 16</li>    
  <li class="odd">Item 17</li>    
  <li class="even">Item 18</li>    
  <li class="odd">Item 19</li>    
  <li class="even">Item 20</li>    
  <li class="odd">Item 21</li>    
  <li class="even">Item 22</li>    
  <li class="odd">Item 23</li>    
  <li class="even">Item 24</li>    
  <li class="odd">Item 25</li>    
  <li class="even">Item 26</li>    
  <li class="odd">Item 27</li>    
  <li class="even">Item 28</li>    
  <li class="odd">Item 29</li>    
  <li class="even">Item 30</li>    
</ul>

Tests:

jQuery
var els = $('.even');
querySelectorAll
var els = document.querySelectorAll('.even');
getElementsByClassName
var els = document.getElementsByClassName('even');
jQuery: mixed selector
var els = $('li.even');
querySelectorAll: mixed selector
var els = document.querySelectorAll('li.even');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
jQuery
querySelectorAll
getElementsByClassName
jQuery: mixed selector
querySelectorAll: mixed selector

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 dive into the explanation of the benchmark.

**Benchmark Definition**

The benchmark measures the performance of three methods to retrieve elements identified by class name:

1. jQuery (`$`): A popular JavaScript library for DOM manipulation.
2. `querySelectorAll`: A standard JavaScript method for selecting elements based on a CSS selector.
3. `getElementsByClassName`: A standard JavaScript method for retrieving elements with a specific class name.

**Options Compared**

The three methods are compared in two variants:

* For jQuery, there are two variants:
	+ `var els = $('.even');`: Retrieves all elements with the class "even" using a single selector.
	+ `var els = $('li.even');`: Retrieves all `<li>` elements with the class "even" using a mixed selector (element type and class name).
* For `querySelectorAll` and `getElementsByClassName`, there are also two variants:
	+ `var els = document.querySelectorAll('.even');`
	+ `var els = document.querySelectorAll('li.even');`

**Pros and Cons**

Here's a brief summary of the pros and cons for each method:

1. **jQuery**
	* Pros: Often faster than standard methods, especially in older browsers, due to caching and other optimizations.
	* Cons: Uses additional JavaScript library code, which can increase page load times. Can also lead to performance issues if not used carefully.
2. **querySelectorAll**
	* Pros: Fast and efficient, with good browser support. Allows for more flexibility in selectors (e.g., attribute queries).
	* Cons: May be slower than jQuery in some cases, especially in older browsers or on very large datasets.
3. **getElementsByClassName**
	* Pros: Simple to use and understand, with good browser support.
	* Cons: Can be slower than `querySelectorAll`, especially for larger datasets.

**Other Considerations**

When choosing a method, consider the following factors:

* Browser support: If you need to support older browsers, jQuery might be a better choice. For modern browsers, `querySelectorAll` and `getElementsByClassName` are usually sufficient.
* DOM size: For very large datasets, `querySelectorAll` might perform better due to its ability to use index arithmetic and other optimizations.
* Readability and maintainability: If you need to write clear and concise code, jQuery's syntax might be more readable. However, this comes at the cost of added library code.

**Alternative Methods**

In addition to the above methods, there are other approaches for retrieving elements by class name:

* `getElementsByTagName`: Retrieves all elements with a specific tag name.
* Attribute queries: Use attribute selectors like `[class="even"]` or `[data-attribute="value"]`.
* CSS-based queries: Use CSS selectors like `.even`, `.odd`, or `li.even`.

These alternative methods might be more suitable for specific use cases, such as:

* Retrieving all elements with a specific tag name.
* Querying attributes dynamically.
* Using CSS to define the selection criteria.

However, they may not always be faster or more efficient than the standard methods mentioned above.

Related benchmarks:

Get elements by class: jQuery vs querySelectorAll vs getElementsByClassName (version: 1)

Compare various methods of obtaining a group of elements identified by class name

Comparing performance of: jQuery vs querySelectorAll vs getElementsByClassName vs jQuery: mixed selector vs querySelectorAll: mixed selector

Created: 9 years ago by: Registered User

Jump to the latest result

jQuery

querySelectorAll

getElementsByClassName

jQuery: mixed selector

querySelectorAll: mixed selector

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):