Benchmark: querySelectorAll vs getElementsByTagName 2z

HTML Preparation code:

<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>

Tests:

querySelectorAll
const allDivs = document.querySelectorAll('div');
getElementsByTagName
const allDivs = Array.from(document.getElementsByTagName('div'));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelectorAll
getElementsByTagName

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in this benchmark and the options being compared.

**What's being tested:**

The benchmark is comparing two ways to select all `div` elements from a HTML document:

1. `document.querySelectorAll('div')`
2. `Array.from(document.getElementsByTagName('div'))`

**Options being compared:**

These two methods are alternatives for selecting multiple elements based on their tag name.

**Pros and Cons of each approach:**

1. `document.querySelectorAll('div')`:
	* Pros:
		+ More concise and readable syntax.
		+ Returns a `NodeList` object, which is more efficient in some cases.
		+ Works with modern browsers.
	* Cons:
		+ May not work with older browsers that don't support the `querySelectorAll` method.
		+ Can be slower than the `getElementsByTagName` approach for very large sets of elements (although this difference is often negligible).
2. `Array.from(document.getElementsByTagName('div'))`:
	* Pros:
		+ Works with all browsers, including older ones.
		+ Returns an array-like object, which can be useful in some cases.
	* Cons:
		+ Less concise and less readable syntax.
		+ Returns a plain JavaScript array, which may not be as efficient as the `NodeList` returned by `querySelectorAll`.

**Library and purpose:**

The only library used in this benchmark is none. Both methods rely on native DOM APIs.

**Special JS feature or syntax:**

There's no special JavaScript feature or syntax being tested here. The focus is on comparing two different approaches to selecting elements from the DOM.

**Other alternatives:**

If you need to select multiple elements based on their tag name, you could also consider using other methods like:

* `document.getElementsById()`: This method returns an array of elements with the specified ID. While it's not directly comparable to `querySelectorAll` or `getElementsByTagName`, it can be useful in certain situations.
* CSS selectors: You could use a CSS selector like `div > *` to select all child elements of `div`. However, this approach has its own set of complexities and is often less efficient than the DOM-based methods.

In summary, the benchmark is testing two alternative ways to select multiple `div` elements from a HTML document: `document.querySelectorAll('div')` vs `Array.from(document.getElementsByTagName('div'))`. The choice between these methods depends on your specific use case, the target browser support, and performance considerations.

Related benchmarks:

querySelectorAll vs getElementsByTagName 2z (version: 0)

Comparing performance of: querySelectorAll vs getElementsByTagName

Created: 5 years ago by: Guest

Jump to the latest result

querySelectorAll

getElementsByTagName

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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