Benchmark: getElementById vs querySelectorqw34re

HTML Preparation code:

<div id="testElement" class="testElement"></div>

Tests:

getElementById
let el = document.getElementById('testElement').innerHTML="h";
querySelector
let el = document.querySelector('#testElement').innerHTML="h";
querySelectorAll
let el = document.querySelectorAll('#testElement').innerHTML="h";
class
let el = document.getElementsByClassName('testElement').innerHTML="h";
selectorClass
let el = document.querySelector('.testElement').innerHTML="h";
AllClass
let el = document.querySelectorAll('.testElement').innerHTML="h";

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById
querySelector
querySelectorAll
class
selectorClass
AllClass

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what is being tested, compared options, pros and cons of each approach, and other considerations.

**Benchmark Overview**

The benchmark measures the performance of different methods to select an element from an HTML document in JavaScript. The test cases are designed to compare the execution speed of `getElementById`, `querySelector`, `querySelectorAll`, and variations of these methods (e.g., using a class selector instead of an ID).

**Methods Being Compared**

1. **`getElementById`**: This method retrieves an element by its ID.
2. **`querySelector`**: This method retrieves an element that matches the specified CSS selector.
3. **`querySelectorAll`**: This method retrieves all elements that match the specified CSS selector.
4. **Class-based selectors** (e.g., `document.getElementsByClassName('testElement')` and `document.querySelector('.testElement')`): These methods retrieve elements based on their class names.

**Options Compared**

Each test case compares two methods:

* The first method is either `getElementById`, `querySelector`, or a class-based selector.
* The second method is the same as the first, but with an additional step (e.g., setting `innerHTML` to "h").

This comparison allows measuring the overhead of each method when executed multiple times.

**Pros and Cons of Each Approach**

1. **`getElementById`**: Pros:
	* Fastest execution speed.
	* Simple and efficient.
2. **`querySelector`**: Pros:
	* More flexible than `getElementById`, as it can match multiple selectors.
	* Can be used for more complex DOM manipulation.
3. **Class-based selectors** (e.g., `document.getElementsByClassName('testElement')`):
	* Pros:
		+ Fast execution speed, similar to `getElementById`.
		+ Simple and efficient.
	* Cons:
		+ Less flexible than `querySelector`, as it can only match class names.
4. **Additional steps**: Adding an extra step (e.g., setting `innerHTML`) increases the overhead of each method.

**Other Considerations**

1. **Library usage**: None of the test cases use external libraries, which simplifies the benchmarking process.
2. **Special JS features or syntax**: The only special feature mentioned is the use of class selectors. However, no other advanced JavaScript features are used in this benchmark.
3. **Browser and device platform**: The benchmark was run on a desktop browser (Firefox 120) with Windows operating system.

**Alternatives**

If you're looking for alternative benchmarks or test cases, consider:

1. **`querySelectorAll` vs `getElementsByClassName`**: This benchmark compares the performance of two methods that retrieve multiple elements.
2. **CSS selector performance**: You can create a benchmark to measure the execution speed of different CSS selectors on various browsers and devices.
3. **DOM manipulation benchmarks**: Create test cases for common DOM manipulation tasks, such as inserting or removing elements, to compare the performance of different JavaScript libraries or built-in methods.

Keep in mind that these alternative benchmarks may require more setup and testing than the provided example, but they can provide valuable insights into specific areas of interest.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:120.0) Gecko/20100101 Firefox/120.0

Browser/OS: Firefox 120 on Windows

View result in a separate tab

Test name	Executions per second
getElementById	440479.1 Ops/sec
querySelector	376821.1 Ops/sec
querySelectorAll	534680.2 Ops/sec
class	4534145.0 Ops/sec
selectorClass	476146.0 Ops/sec
AllClass	646207.8 Ops/sec

Related benchmarks:

getElementById vs querySelectorqw34re (version: 1)

Comparing performance of: getElementById vs querySelector vs querySelectorAll vs class vs selectorClass vs AllClass

Created: one year ago by: Registered User

Jump to the latest result

getElementById

querySelector

querySelectorAll

class

selectorClass

AllClass

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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