Benchmark: GetElementById vs GetElementByTag v2

HTML Preparation code:

<div id="unique" class="unique" name="unique" data-unique="1">test</div>
<unique-custom id="unique-custom" class="unique-custm" name="unique-custom" data-unique-custom="1">unique custom</unique-custom>

Script Preparation code:

var i, imax;
var doc = document;
var customElementRegistry = window.customElements;
customElementRegistry.define("unique-custom", class MyCustomElement extends HTMLElement {
  constructor() {
    // Always call super first in constructor
    super();
  }});

Tests:

GetElementById
var test = doc.getElementById('unique').innerHTML;
GetElementByTag
var formelem = doc.getElementsByTagName('unique-custom')[0].innerHTML;
GetElementByClassname
var test = doc.getElementsByClassName('unique')[0].innerHTML;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
GetElementById
GetElementByTag
GetElementByClassname

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 dive into the explanation of what is tested in this benchmark and the options being compared.

**Benchmark Overview**

The test case compares three ways to retrieve an HTML element: `GetElementById`, `GetElementByTag`, and `GetElementByClassname`. The goal is to measure which approach is faster.

**Options Being Compared**

1. **`GetElementById`**: This method retrieves the first element whose id attribute matches the specified value.
2. **`GetElementByTag`**: This method retrieves all elements with the specified tag name and returns the first one (if any).
3. **`GetElementByClassname`**: This method retrieves all elements with the specified class name and returns the first one (if any).

**Pros and Cons of Each Approach**

* `GetElementById`:
	+ Pros: Fast, reliable, and widely supported.
	+ Cons: Can be slow if there are many elements with the same id attribute.
* `GetElementByTag`:
	+ Pros: Simple to implement and can be fast for simple cases.
	+ Cons: Can return multiple results, making it slower than `GetElementById`.
	+ Additional con: May not work as expected in all cases (e.g., when using tag names with spaces).
* `GetElementByClassname`:
	+ Pros: Similar to `GetElementById` but can be faster for elements with unique class names.
	+ Cons: Can return multiple results, making it slower than `GetElementById`.

**Library Usage**

In the benchmark preparation code, a custom element (`unique-custom`) is defined using the `window.customElements.define()` method. This library allows creating custom HTML elements without relying on vendor prefixes.

The `MyCustomElement` class extends the native `HTMLElement` class and provides a unique identifier for the custom element. The `customElementRegistry` variable stores references to all registered custom elements.

**Special JS Features/Syntax**

This benchmark does not use any special JavaScript features or syntax, such as ES6 classes, async/await, or Promises.

**Other Alternatives**

If you're interested in alternative approaches, here are a few options:

1. **`querySelector` and `querySelectorAll`**: These methods can be used to select elements using CSS selectors.
2. **`getElementsByTagName`**: This method is similar to `GetElementByTag`, but it returns an array of all matching elements, not just the first one.
3. **`getElementsByClassName`**: This method is similar to `GetElementByClassname`, but it returns an array of all matching elements, not just the first one.

Note that these alternatives may have different performance characteristics and might require additional setup or modifications to your code.

Related benchmarks:

GetElementById vs GetElementByTag v2 (version: 0)

Comparing performance of: GetElementById vs GetElementByTag vs GetElementByClassname

Created: 2 years ago by: Guest

Jump to the latest result

GetElementById

GetElementByTag

GetElementByClassname

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):