Benchmark: #el selector vs div#el selector

HTML Preparation code:

<script src="//code.jquery.com/jquery-3.4.0.slim.min.js"></script>
<div id="foo" class="foo2"></div>

Tests:

div#el selector
var el = $("div#foo"); var className = el.className;
#el selector
var el = $("#foo"); var className = el.className;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
div#el selector
#el selector

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is crucial for creating efficient and high-performance applications. In this case, we're analyzing the MeasureThat.net benchmark that compares two different approaches to select an HTML element.

**Benchmark Definition**

The benchmark definition specifies a comparison between two methods of selecting an HTML element: using a CSS selector (`div#el`) and a jQuery selector (`$(\"div#foo\")`).

**Options Compared**

We have two options being compared:

1. **CSS Selector**: `div#el`
2. **jQuery Selector**: `$(\"div#foo\")`

**Pros and Cons of Each Approach:**

**CSS Selector (div#el)**

Pros:

* Fast and lightweight
* No additional library dependency required
* Works well for simple, static DOM structures

Cons:

* May not work as expected in complex or dynamic DOM structures
* Less flexible than jQuery selectors for certain use cases

**jQuery Selector ($(\"div#foo\")**

Pros:

* More flexible and powerful than CSS selectors for certain use cases (e.g., nested selectors)
* Can handle more complex DOM structures
* Often faster than CSS selectors for large datasets

Cons:

* Requires an additional library dependency (`jQuery` in this case)
* May add overhead due to the library's initialization and execution of methods like `$()`

**Library: jQuery**

In this benchmark, jQuery is used as a utility library to provide its `$(selector)` function for selecting DOM elements. The use of jQuery allows for more flexible and powerful selectors, but also adds an additional layer of complexity.

**Special JS Feature or Syntax: None mentioned**

There are no special JavaScript features or syntaxes being tested in this benchmark.

**Other Alternatives:**

For element selection, other libraries like `Sizzle` (the engine behind jQuery) or pure CSS-based selectors can be used. Additionally, some modern JavaScript frameworks and libraries like React or Angular provide their own DOM querying mechanisms.

**Benchmark Preparation Code and Test Cases**

The provided benchmark preparation code sets up a basic HTML page with an `id`-qualified element (`<div id="foo">`). The test cases then define the two different approaches to select this element, using either a CSS selector or a jQuery selector. These test cases are executed multiple times to measure their performance.

**Latest Benchmark Result**

The latest benchmark results show that:

* The **jQuery Selector** approach is faster than the **CSS Selector** approach for this specific test case.
* Both approaches have a relatively high execution rate, indicating good performance in this scenario.

Keep in mind that the actual performance differences may vary depending on the specific use case and environment.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Linux; Android 9; SM-A750G) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.93 Mobile Safari/537.36

Browser/OS: Chrome Mobile 79 on Android

View result in a separate tab

Test name	Executions per second
div#el selector	113949.4 Ops/sec
#el selector	385537.9 Ops/sec

Related benchmarks:

#el selector vs div#el selector (version: 0)

Comparing performance of: div#el selector vs #el selector

Created: 4 years ago by: Guest

Jump to the latest result

div#el selector

#el selector

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):