Benchmark: jquery level selector

HTML Preparation code:

<div id="test">
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
 <div class="level1"><div class="level2"></div></div>
</div>

Tests:

children .level1
$('#test').children('.level1');
children div.level1
$('#test').children('div.level1');
find .level1
$('#test').find('.level1');
find div.level1
$('#test').find('div.level1');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
children .level1
children div.level1
find .level1
find div.level1

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the provided benchmark and its options.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided benchmark measures the performance of different selectors in jQuery, specifically `children` and `find`.

The benchmark consists of four test cases:

1. `children .level1`
2. `children div.level1`
3. `find .level1`
4. `find div.level1`

Each test case uses a similar HTML structure with multiple nested elements.

**Options Compared**

The options compared in this benchmark are:

* `children`: selects all child elements of the specified element.
* `children .class`: selects all child elements that match the specified class (in this case, `.level1`).
* `find`: selects the first element that matches the specified selector.
* `find .class`: selects the first element that matches the specified class (in this case, `.level1`).

**Pros and Cons of Each Approach**

Here's a brief overview of the pros and cons of each approach:

* **`children`**: This method is generally faster because it avoids the overhead of parsing CSS selectors. However, it can be less efficient if the element has many child elements that don't match the specified class.
* `children .class`: This method is slower than `children` because it requires additional processing to parse the class selector. However, it's more efficient than `find` for large datasets.
* **`find`**: This method is generally slower than both `children` and `children .class` because it requires more overhead to parse the CSS selector. However, it's a safer choice if you're not sure what elements to match, as it stops at the first match.
* `find .class`: Similar to `children .class`, this method is slower than `children` but faster than `find`. It's a good balance between performance and safety.

**Library Used**

In this benchmark, jQuery is used as the library. jQuery provides an efficient way to select elements on the DOM, and its selector engine is optimized for performance.

**Special JS Features or Syntax**

None of the provided test cases use any special JavaScript features or syntax that would affect their performance significantly. However, it's worth noting that some browsers may have different optimizations or quirks when executing these selectors.

**Other Alternatives**

If you wanted to write a benchmark like this using a framework other than jQuery, you could consider using:

* DOM manipulation libraries like React or Angular
* CSS-in-JS solutions like Styled Components or Emotion
* Frameworks that provide built-in selector engines, such as Vue.js or Preact

Keep in mind that the performance characteristics of these alternatives may vary depending on the specific use case and browser support.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36

Browser/OS: Chrome 53 on Windows 7

View result in a separate tab

Test name	Executions per second
children .level1	88294.2 Ops/sec
children div.level1	76425.9 Ops/sec
find .level1	214683.4 Ops/sec
find div.level1	65713.4 Ops/sec

Related benchmarks:

jquery level selector (version: 0)

Comparing performance of: children .level1 vs children div.level1 vs find .level1 vs find div.level1

Created: 8 years ago by: Guest

Jump to the latest result

children .level1

children div.level1

find .level1

find div.level1

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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