Benchmark: jQuery class selector

HTML Preparation code:

<div id='curBody1'>
  <div>
    <span>
      <div>
        This is a div we're NOT looking for.
      </div>
    </span>
  </div>
</div>
<div id='curBody2'>
  <div>
    <span>
      <div class='desired-element'>
        This is the div we're looking for.
      </div>
    </span>
  </div>
</div>

Script Preparation code:

var curElement = null;

Tests:

Id and class chaining selector
curElement = $('#curBody2 .desired-element');
Class selector only
curElement = $('.desired-element');
Id selector then .find
curElement = $('#curBody2').find('.desired-element');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Id and class chaining selector
Class selector only
Id selector then .find

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.116 Safari/537.36

Browser/OS: Chrome 52 on Windows

View result in a separate tab

Test name	Executions per second
Id and class chaining selector	108490.9 Ops/sec
Class selector only	562638.4 Ops/sec
Id selector then .find	423420.4 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON benchmark definition and test cases.

**Benchmark Definition**

The first part of the JSON represents the overall benchmark. Here, we have:

* `Name`: The name of the benchmark, which is "jQuery class selector".
* `Description`: A brief description of what the benchmark tests, which is selecting an element using its class vs getting a handle on the parent element and then navigating to the child.
* `Script Preparation Code` and `Html Preparation Code`: These are code snippets that prepare the JavaScript environment and HTML structure for the benchmark.

**Individual Test Cases**

The test cases define three different scenarios:

1. **Id and Class Chaining Selector**
	* The script tries to select an element using its ID (`#curBody2`) and then navigate to a child element with the class `desired-element` (`curElement = $('#curBody2 .desired-element');`).
	* This approach involves two DOM lookups, which might be slower than other approaches.
	* **Pros**: Easy to read and understand. Allows for direct navigation to a specific element without relying on class names.
	* **Cons**: Requires two DOM lookups, which can increase the time taken to execute the benchmark.
2. **Class Selector Only**
	* The script tries to select an element using its class name (`curElement = $('.desired-element');`).
	* This approach only involves one DOM lookup and relies on the browser's CSS selectors to find the desired element.
	* **Pros**: Simplifies the code and reduces the number of DOM lookups. Can be faster than other approaches since it leverages CSS selectors.
	* **Cons**: May not work as expected in older browsers that don't support modern CSS selectors. May require more complex CSS rules to achieve the desired result.
3. **Id Selector then .find**
	* The script tries to select an element using its ID (`#curBody2`) and then use the `.find()` method to navigate to a child element with the class `desired-element` (`curElement = $('#curBody2').find('.desired-element');`).
	* This approach involves two DOM lookups: one for the parent element (ID) and another for the child element (class). The `.find()` method is only used to narrow down the search results.
	* **Pros**: Easy to read and understand. Allows for direct navigation to a specific element without relying on class names.
	* **Cons**: Requires two DOM lookups, which can increase the time taken to execute the benchmark.

**Library Used**

The `jQuery` library is used in all test cases. jQuery provides an easy way to select elements using various selectors (e.g., IDs, classes, and tags). The `.find()` method is used to navigate to child elements.

**Special JS Features or Syntax**

None of the test cases use special JavaScript features or syntax, such as async/await or promises.

**Other Alternatives**

If you want to compare other approaches, here are a few examples:

1. **CSS Selectors only**: Use CSS selectors like `#curBody2 .desired-element` without using jQuery's `querySelector()` or `.find()` methods.
	* **Pros**: Simplifies the code and reduces the number of DOM lookups. Can be faster than other approaches since it leverages CSS selectors.
	* **Cons**: May not work as expected in older browsers that don't support modern CSS selectors.
2. **Native JavaScript DOM Lookups**: Use native JavaScript methods like `document.getElementById()` or `document.querySelector()` to select elements directly from the DOM.
	* **Pros**: Simplifies the code and reduces the number of dependencies. Can be faster than other approaches since it leverages native JavaScript APIs.
	* **Cons**: May not work as expected in older browsers that don't support modern CSS selectors.

Keep in mind that these alternative approaches might require more complex code or additional libraries, so they may not always be the best choice depending on your specific use case.

Related benchmarks:

jQuery class selector (version: 0)

This will test the difference between selecting an element using its class vs getting a handle on the parent element and then navigating to the child.

Comparing performance of: Id and class chaining selector vs Class selector only vs Id selector then .find

Created: 8 years ago by: Guest

Jump to the latest result

Id and class chaining selector

Class selector only

Id selector then .find

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 2 months ago):