Benchmark: getElementById vs querySelector vs getElementsByTagName pt. 2

HTML Preparation code:

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

Tests:

getElementById
var el = document.getElementById('testElement'); var className = el.className;
querySelector element ID
var el = document.querySelector('#testElement'); var className = el.className;
querySelector tag name
var el = document.querySelector('div'); var className = el.className;
getElementsByTagName
var el = document.getElementsByTagName('div'); var className = el.className;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById
querySelector element ID
querySelector tag name
getElementsByTagName

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_0_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.0.1 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 18 on iOS 18.0.1

View result in a separate tab

Test name	Executions per second
getElementById	8926841.0 Ops/sec
querySelector element ID	3694735.8 Ops/sec
querySelector tag name	4168903.2 Ops/sec
getElementsByTagName	7583361.5 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, along with the pros and cons of each approach.

**Benchmark Overview**

The benchmark compares the performance of four methods to retrieve an element from a HTML document:

1. `getElementById`
2. `querySelector` (using ID)
3. `querySelector` (using tag name)
4. `getElementsByTagName`

**Options Compared**

Here's a brief description of each option and their pros and cons:

1. **`getElementById`**:
	* Pros: Fast, reliable, and widely supported.
	* Cons: Can be slower for elements with multiple IDs or complex DOM structures.
2. **`querySelector` (using ID)**:
	* Pros: More flexible than `getElementById`, can also retrieve elements by class names, attributes, or CSS selectors.
	* Cons: May be slower due to the complexity of the selector and potential DOM traversals.
3. **`querySelector` (using tag name)**:
	* Pros: Similar to using ID, but with more flexibility in terms of element selection.
	* Cons: Still may be slower than `getElementById` or `getElementsByTagName`.
4. **`getElementsByTagName`**:
	* Pros: Fast and reliable, especially for simple DOM structures.
	* Cons: May be slower for complex DOM structures or elements with multiple tags.

**Library Usage**

None of the test cases use a library, so there's no additional overhead to consider.

**Special JavaScript Features or Syntax**

The benchmark uses the following special features:

* `querySelector` and `querySelectorAll` are used in various test cases. These methods are part of the W3C DOM Standard and provide a flexible way to select elements.
* The `getElementsByClassName`, `getElementsByTagName`, and `getElementById` methods are also used. While not as powerful as `querySelector`, these methods can still be useful for specific use cases.

**Other Alternatives**

If you're looking for alternative benchmarks or tests, here are some options:

1. **Browser-specific benchmarks**: Measure the performance of different browsers using their own benchmarking tools.
2. **Web performance benchmarks**: Compare the performance of different web technologies, such as HTML5, CSS3, and WebSockets.
3. **DOM manipulation benchmarks**: Test the performance of various DOM manipulation methods, such as inserting, removing, or updating elements.

For a more detailed analysis of the benchmark results, you can examine the "ExecutionsPerSecond" value for each test case, which indicates how many times the specified method was executed in one second. This will give you an idea of which method is fastest and most efficient under different conditions.

Related benchmarks:

getElementById vs querySelector vs getElementsByTagName pt. 2 (version: 0)

Comparing performance of: getElementById vs querySelector element ID vs querySelector tag name vs getElementsByTagName

Created: 4 years ago by: Guest

Jump to the latest result

getElementById

querySelector element ID

querySelector tag name

getElementsByTagName

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):