Benchmark: querySelectorAll vs getElementsByClassName Test2

HTML Preparation code:

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Tests:

querySelector
document.querySelectorAll(".test")
getElementsByClassName
document.getElementsByClassName("test")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelector
getElementsByClassName

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.114 Safari/537.36

Browser/OS: Chrome 89 on Mac OS X 11.2.3

View result in a separate tab

Test name	Executions per second
querySelector	923978.8 Ops/sec
getElementsByClassName	3568829.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript benchmarks!

**What is being tested?**

MeasureThat.net is testing two DOM query methods: `querySelectorAll` and `getElementsByClassName`. Specifically, it's comparing the performance of these two methods when selecting elements with the class "test" from a HTML document.

**Options compared:**

There are two main options being compared:

1. **`document.querySelectorAll(".test")`**: This method returns a NodeList containing all elements that match the specified CSS selector (`".test"`).
2. **`document.getElementsByClassName("test")`**: This method returns an HTMLCollection containing all elements with the specified class name (`"test"`).

**Pros and Cons of each approach:**

1. `document.querySelectorAll(".test")`:
	* Pros: More flexible and powerful, as it can select multiple elements based on a CSS selector.
	* Cons: May have slower performance due to the need to parse the DOM and execute the query.
2. `document.getElementsByClassName("test")`:
	* Pros: Faster performance, as it directly accesses the element with the specified class name without needing to parse the DOM.
	* Cons: Less flexible and powerful than `querySelectorAll`, as it only returns a single element.

**Other considerations:**

* Both methods have different performance characteristics due to the way they interact with the DOM. `querySelectorAll` may be slower because of the need to create a new NodeList, while `getElementsByClassName` is faster since it directly accesses the element.
* The choice between these two methods depends on the specific use case and requirements.

**Library used:**

None are mentioned in the provided benchmark definition or result.

**Special JS feature or syntax:**

None are explicitly mentioned. However, the use of CSS selectors (`".test"` and `getElementsByClassName`) relies on some JavaScript-specific features:

* `document.querySelectorAll()` and `document.getElementsByClassName()` are built-in methods of the Document object.
* CSS selectors can be used to select elements based on their attributes, class names, IDs, and more.

**Other alternatives:**

If you need to perform DOM queries in JavaScript, other methods might include:

1. `querySelector` (a similar method to `querySelectorAll`, but returns a single element instead of a NodeList).
2. `getElementById()` or `getElementsByTagName()` (which return an individual element or a collection of elements by ID or tag name, respectively).
3. `Element.prototype.matches()` and `Element.prototype.matchesAll()` (introduced in ECMAScript 2017, these methods are similar to CSS selectors but return a boolean value indicating whether the element matches or does not match the selector).

Keep in mind that each method has its own strengths and weaknesses, and choosing the right one depends on your specific use case and requirements.

Related benchmarks:

querySelectorAll vs getElementsByClassName Test2 (version: 0)

Comparing performance of: querySelector vs getElementsByClassName

Created: 3 years ago by: Guest

Jump to the latest result

querySelector

getElementsByClassName

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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