Benchmark: foobar-ccmpcp-4 - MeasureThat.net

HTML Preparation code:

<html>
  <head>
  </head>
  <body>
    <div id=''></div>
  </body>
</html>

Tests:

querySelector
document.querySelector('body');
querySelectorAll
document.querySelectorAll('body');
getElementsByTagName
document.getElementsByTagName('body')[0];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelector
querySelectorAll
getElementsByTagName

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is being tested?**

The provided JSON represents three individual test cases that measure the performance of different methods for selecting DOM elements in JavaScript:

1. `document.querySelector('body')`
2. `document.querySelectorAll('body')`
3. `document.getElementsByTagName('body')[0]`

These methods are used to retrieve a single or multiple HTML elements with a specific selector.

**Options compared**

The three options being compared are:

* `querySelector`: A method that returns the first element matching the specified selector.
* `querySelectorAll`: A method that returns a NodeList containing all elements matching the specified selector.
* `getElementsByTagName`: A method that returns an HTMLCollection of all elements with the specified tag name.

**Pros and Cons**

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

1. **querySelector**:
	* Pros: More efficient than `getElementsByTagName` since it only retrieves one element, reducing memory allocation and garbage collection overhead.
	* Cons: Returns only the first matching element, so if there are multiple elements, it will return the first one.
2. **querySelectorAll**:
	* Pros: Returns all matching elements, making it suitable for situations where you need to process a list of elements.
	* Cons: Can be slower than `querySelector` since it needs to allocate memory for a NodeList and iterate over its length.
3. **getElementsByTagName**:
	* Pros: Simple and widely supported, as it's part of the DOM API.
	* Cons: Inefficient compared to `querySelector`, especially when dealing with large documents or multiple elements.

**Library usage**

In this benchmark, none of the libraries are explicitly mentioned in the provided JSON data. However, JavaScript engines like V8 (used by Chrome) and SpiderMonkey (used by Firefox) provide built-in support for these DOM methods.

**Special JS feature/syntax**

None of the test cases use any special JavaScript features or syntax that would require additional explanation.

**Other alternatives**

If you're interested in exploring alternative approaches, here are a few:

* `getElementsByClassName` and `getElementById` can be used as alternatives to `querySelector` and `querySelectorAll`, respectively.
* Modern web browsers also provide newer methods like `document.querySelector(':has')` and `document.querySelectorAll(':has')` for more complex selectors.

Keep in mind that these alternative approaches might have different performance characteristics, so it's essential to test them thoroughly if you suspect they would be better suited for your use case.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36

Browser/OS: Chrome 73 on Mac OS X 10.12.6

View result in a separate tab

Test name	Executions per second
querySelector	3085033.0 Ops/sec
querySelectorAll	977220.9 Ops/sec
getElementsByTagName	2983347.8 Ops/sec

Related benchmarks:

foobar-ccmpcp-4 (version: 0)

Comparing performance of: querySelector vs querySelectorAll vs getElementsByTagName

Created: 5 years ago by: Guest

Jump to the latest result

querySelector

querySelectorAll

getElementsByTagName

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):