Benchmark: getElementsByClassName vs querySelectorAll - rhymes

HTML Preparation code:

<body>
  <div class="js-something">
  </div>
</body>

Tests:

getElementsByClassName
document.getElementsByClassName("js-something")
querySelectorAll
document.querySelectorAll(".js-something")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementsByClassName
querySelectorAll

Fastest: N/A

Slowest: N/A

Latest run results:

No previous 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 dive into the world of JavaScript microbenchmarks and explore what's being tested on MeasureThat.net.

**Benchmark Definition**

The benchmark definition is provided in JSON format, which describes two test cases:

1. `document.getElementsByClassName("js-something")`
2. `document.querySelectorAll(".js-something")`

Both tests aim to measure the performance difference between using `getElementsByClassName` and `querySelectorAll` to select elements with a specific class.

**Options Compared**

The benchmark compares the following options:

* `getElementsByClassName`: This method returns an array-like object containing all elements that match the specified value, in this case, `"js-something"`.
* `querySelectorAll`: This method returns a NodeList containing all elements that match the specified CSS selector, also `"." + "js-something"`.

**Pros and Cons of Each Approach**

Here are some pros and cons of each approach:

* `getElementsByClassName`:
	+ Pros: More compatible with older browsers (IE 6-8), allows for attributes to be tested.
	+ Cons: Returns an array-like object, can be slower due to DOM traversal.
* `querySelectorAll`:
	+ Pros: More modern and efficient, works with CSS selectors, faster DOM access.
	+ Cons: Requires a compatible browser, may not work with older browsers or non-standard attributes.

**Library Usage**

In this benchmark, no libraries are explicitly mentioned. However, both methods use the Document Object Model (DOM) to interact with HTML elements.

**Special JS Features/Syntax**

There's no mention of special JavaScript features or syntax in this benchmark. The focus is on comparing two simple method calls.

**Other Alternatives**

If you're looking for alternatives to these methods, consider:

* `querySelector` and `querySelectorAll` (similar to `getElementsByClassName` and `querySelectorAll`, but with improved CSS selector support)
* `querySelectorAll` with a CSS selector that uses a pseudo-class or attribute, such as `[data-tag="something"]`
* `element.matches()` (a more modern approach for checking element matches)

For measuring performance in JavaScript, other alternatives include:

* V8 and SpiderMonkey benchmarks from Mozilla
* benchmark.js (a simple benchmarking library)
* js-benchmark (a comprehensive benchmarking framework)

In summary, the MeasureThat.net benchmark provides a clear comparison between `getElementsByClassName` and `querySelectorAll`, highlighting their strengths and weaknesses. Understanding these differences is crucial for optimizing DOM manipulation in your JavaScript applications.

Related benchmarks:

getElementsByClassName vs querySelectorAll - rhymes (version: 0)

Comparing performance of: getElementsByClassName vs querySelectorAll

Created: 5 years ago by: Guest

Jump to the latest result

getElementsByClassName

querySelectorAll

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):