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

Latest run results:

Run details: (Test run date: 2 years 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

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

Related benchmarks:

getElementById vs querySelectorqw34re (version: 1)

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

Created: 2 years ago by: Registered User

Jump to the latest result

getElementById

querySelector

querySelectorAll

class

selectorClass

AllClass

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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