Benchmark: meta tag selection

HTML Preparation code:

<meta name="meow"/>

Tests:

tagname
var m = document.getElementsByTagName('meow');
query
var m = document.head.querySelector("meta[name='meow']")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
tagname
query

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Measuring JavaScript performance! Let's dive into the world of microbenchmarks and explore what's being tested in this specific benchmark.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that tests two different approaches for selecting a meta tag using the `document` object. The test cases aim to measure the execution time, speed, or performance difference between these two methods.

**Options compared:**

1. **`getElementsByTagName`**: This method returns an HTMLCollection of all elements with the specified tag name. In this case, it's used to retrieve a meta tag with the name "meow".
2. **`querySelector` and `querySelectorAll` with `document.head`**: These methods allow you to select elements by their CSS selectors or attribute names, respectively. Here, it's used to target the first `<meta>` element in the `head` section of the HTML document.

**Pros and Cons:**

* **`getElementsByTagName`**:
	+ Pros: Simple and widely supported (most browsers).
	+ Cons: Returns a collection of elements, which can lead to slower performance due to the need to iterate over the collection.
* **`querySelector` and `querySelectorAll` with `document.head`**:
	+ Pros: More efficient and flexible than `getElementsByTagName`, especially for targeting specific elements by CSS selector or attribute name. It's also a more modern approach, introduced in ECMAScript 5 (2009).
	+ Cons: May not work as expected if the meta tag is dynamically inserted or removed.

**Library and its purpose:**

In this benchmark, no specific library is used beyond what comes with the standard JavaScript `document` object. However, the use of `querySelector` and `querySelectorAll` suggests familiarity with modern web development techniques.

**Special JS feature/syntax:**

This benchmark does not specifically test any special JavaScript features or syntax, such as async/await, Promises, or arrow functions. It's a straightforward performance comparison between two simple DOM manipulation methods.

**Other alternatives:**

For more advanced scenarios, you might consider using:

* `querySelector` and `querySelectorAll` with CSS selectors to target elements.
* Querying the document body (`document.body`) instead of the head section.
* Using `getElementsByAttribute()` or `getAttribute()` for attribute-based selections.
* Leveraging modern web APIs like Web Content Access API (WCAB) or DOM Events.

These alternatives might provide better performance, flexibility, or compatibility, depending on your specific use case.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.111 Safari/537.36

Browser/OS: Chrome 86 on Windows

View result in a separate tab

Test name	Executions per second
tagname	2871890.8 Ops/sec
query	2538960.2 Ops/sec

Related benchmarks:

meta tag selection (version: 0)

Comparing performance of: tagname vs query

Created: 7 years ago by: Guest

Jump to the latest result

tagname

query

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):