Benchmark: querySelector vs querySelectorAll vs getElementsByClassName vs querySelector (ID) vs getElementsByID — (getElementsByClassName sem .(ponto))

HTML Preparation code:

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

Tests:

querySelector
document.querySelector(".test")
querySelectorAll
document.querySelectorAll(".test")
getElementsByClassName
document.getElementsByClassName("test")
querySelector (ID)
document.querySelector("#test")
getElementsByID
document.getElementById("test")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelector
querySelectorAll
getElementsByClassName
querySelector (ID)
getElementsByID

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Measuring performance differences between various DOM query methods is crucial in web development, as it can significantly impact the user experience and overall application performance.

**Benchmark Overview**

The provided JSON represents a benchmarking test that compares the performance of five different DOM query methods:

1. `querySelector`
2. `querySelectorAll`
3. `getElementsByClassName`
4. `querySelector` with an ID (e.g., `document.querySelector("#test")`)
5. `getElementsByID`

**Options Comparison**

Each option has its pros and cons:

1. **`querySelector`**: This method is the most efficient, as it only returns one element if a single match is found. However, it can be slower for larger datasets or when searching for multiple elements.
2. **`querySelectorAll`**: This method returns all matching elements in an array. It's often faster than `querySelector`, but may return more results than needed.
3. **`getElementsByClassName`**: This method returns a collection of elements with the specified class name. It can be slower due to the need to iterate over the DOM tree and filter results.
4. **`querySelector` with ID**: This variant is similar to `querySelector`, but it's optimized for IDs, which are often used as selectors in web development.

In general:

* Fastest: `querySelector`
* Suitable for most cases: `querySelectorAll`
* Use when exact class name is needed: `getElementsByClassName`

**Library Considerations**

None of the provided options rely on any specific JavaScript library beyond the standard DOM APIs. However, some libraries like jQuery might use similar methods under the hood.

**Special JS Feature/Syntax**

There's no mention of special JavaScript features or syntax in this benchmark. The focus is solely on comparing the performance of different DOM query methods.

**Other Alternatives**

If you need to measure the performance of other DOM query methods, consider exploring:

* `querySelectorNode`
* `getElementsByTagNames`
* `getElementById`
* `document.querySelectorAll` with specific selectors (e.g., `div#test`)

Keep in mind that each method has its strengths and weaknesses, and choosing the right one depends on your specific use case.

In summary, this benchmark provides a solid foundation for understanding the performance differences between various DOM query methods. By analyzing the results, you can make informed decisions about which method to use in your web development projects.

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.130 Safari/537.36

Browser/OS: Chrome 79 on Mac OS X 10.15.2

View result in a separate tab

Test name	Executions per second
querySelector	4160093.8 Ops/sec
querySelectorAll	1683973.5 Ops/sec
getElementsByClassName	4936644.5 Ops/sec
querySelector (ID)	2898815.0 Ops/sec
getElementsByID	5705006.5 Ops/sec

Related benchmarks:

querySelector vs querySelectorAll vs getElementsByClassName vs querySelector (ID) vs getElementsByID — (getElementsByClassName sem .(ponto)) (version: 0)

Comparing performance of: querySelector vs querySelectorAll vs getElementsByClassName vs querySelector (ID) vs getElementsByID

Created: 5 years ago by: Registered User

Jump to the latest result

querySelector

querySelectorAll

getElementsByClassName

querySelector (ID)

getElementsByID

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):