Benchmark: getElementById vs ParentElement.children

HTML Preparation code:

<div id="test_element_id" class="test_element_class"></div>

Script Preparation code:

var p = document.getElementById('test_element_id').parentElement;

Tests:

getElementById
var el = document.getElementById('test_element_id'); var className = el.className;
children
var el = p.children['test_element_id']; var className = el.className;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById
children

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/115.0

Browser/OS: Firefox 115 on Linux

View result in a separate tab

Test name	Executions per second
getElementById	5719495.5 Ops/sec
children	7585461.5 Ops/sec

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 JavaScript microbenchmark.

**Benchmark Definition**

The benchmark is comparing two approaches to retrieve the `className` property of an HTML element:

1. `document.getElementById('test_element_id')`
2. `p.children['test_element_id']`

where `p` is a reference to the parent element retrieved using `document.getElementById('test_element_id').parentElement`.

**Options being compared**

The two options being compared are:

* Using `document.getElementById()` to retrieve an element by its ID and then accessing its child elements
* Using `children` property of the parent element's `p` object to directly access a specific child element

**Pros and Cons**

1. **Using `document.getElementById()`:**
	* Pros:
		+ Wide browser support (most modern browsers)
		+ Easy to understand and use for developers familiar with traditional DOM methods
	* Cons:
		+ May be slower due to the additional lookup step
2. **Using `children` property:**
	* Pros:
		+ Faster lookup since it directly accesses a specific child element
	* Cons:
		+ Requires knowledge of the parent element's structure and is more complex

**Library and purpose**

There doesn't appear to be any library used in this benchmark.

**Special JavaScript features or syntax**

There are no special JavaScript features or syntax mentioned in this benchmark. However, it's worth noting that using `children` property can be considered a modern DOM method, which may not be supported by all browsers.

**Other alternatives**

For similar use cases, other approaches could include:

* Using `document.querySelector()` to select the element based on its ID and then accessing its child elements
* Using CSS selectors (e.g., `#test_element_id > .class`) to access specific elements

Keep in mind that the performance differences between these methods can be significant, especially for large datasets or complex DOM structures.

**Benchmark preparation code**

The provided script preparation code creates a reference to the parent element using `document.getElementById('test_element_id').parentElement` and assigns it to variable `p`. The HTML preparation code defines an HTML element with the ID `test_element_id` and class `test_element_class`.

**Test cases**

The two test cases compare the performance of:

1. Retrieving the `className` property using `document.getElementById()`
2. Retrieving the `className` property using `children` property of the parent element's `p` object

These test cases are likely used to compare the performance of these two approaches in a controlled environment, allowing users to see which method is faster and more efficient.

Related benchmarks:

getElementById vs ParentElement.children (version: 0)

Comparing performance of: getElementById vs children

Created: 2 years ago by: Guest

Jump to the latest result

getElementById

children

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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