Benchmark: DOM traversal - MeasureThat.net

HTML Preparation code:

<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="bar"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>
<p class="foo"></p>

Tests:

querySelector
document.querySelector('.bar')
getElementsByClassName
document.getElementsByClassName('bar')

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: 7 years ago)

User agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0

Browser/OS: Firefox 52 on Ubuntu

View result in a separate tab

Test name	Executions per second
querySelector	92995.5 Ops/sec
getElementsByClassName	23396560.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its options.

**What is tested?**

The provided benchmark measures the performance of two DOM traversal methods: `document.querySelector` and `document.getElementsByClassName`. These methods are used to select elements within an HTML document using CSS selectors.

**Options compared**

Two options are being compared:

1. **`document.querySelector('.bar')`**: This method uses a single selector (`'.bar'`) to select an element that matches the specified class.
2. **`document.getElementsByClassName('bar')`**: This method uses a multiple selector (`'[class=bar]'`) to select all elements that have the `bar` class.

**Pros and cons of each approach**

1. **`document.querySelector('.bar')`**
	* Pros:
		+ More efficient, as it only selects one element.
		+ Less overhead due to the use of a single selector.
	* Cons:
		+ May not find all elements with the specified class if there are multiple classes or attributes on the element.
2. **`document.getElementsByClassName('bar')`**
	* Pros:
		+ Guarantees finding all elements with the specified class, even if they have additional classes or attributes.
	* Cons:
		+ More overhead due to the use of a multiple selector and iterating over all matching elements.

**Library usage**

The `getElementsByClassName` method uses the `Element.prototype.getElementsByClassName` method from the W3C DOM specification. This method is part of the ECMAScript standard, ensuring compatibility across different browsers.

**Special JS feature or syntax**

There are no special JavaScript features or syntaxes being used in this benchmark.

**Other alternatives**

If you wanted to compare other DOM traversal methods, some alternatives could be:

1. `document.getElementsByTagName('p')` (using a single tag name)
2. `document.querySelectorAll('.bar')` (using the CSS query selector API)
3. `document.querySelectorAll('.bar')` (also using the CSS query selector API)

However, these alternatives would not necessarily provide the same level of performance comparison as the original benchmark, which specifically focuses on comparing the efficiency of `querySelector` and `getElementsByClassName`.

Related benchmarks:

DOM traversal (version: 0)

Yeah!

Comparing performance of: querySelector vs getElementsByClassName

Created: 8 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):