Benchmark: tag VS class - MeasureThat.net

HTML Preparation code:

<div class="hello" id="hello" data-hello>Hello</div>

Tests:

class
document.querySelector('.hello');
tag
document.querySelector('div');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
class
tag

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36

Browser/OS: Chrome 129 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
class	4295417.5 Ops/sec
tag	4452271.0 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 provided benchmarking setup and analyze what's being tested, compared, and considered.

**What is being tested?**

The main objective of this benchmark is to compare the performance of two different approaches: using class selectors (`class`) versus using tag selectors (`tag`). The test case "document.querySelector('.hello');" is used to measure the performance of both approaches.

**Options compared**

Two options are being compared:

1. **Class selectors (`class`)**: This approach uses a dot (`.`) followed by a space and then the class name to select elements.
2. **Tag selectors (`tag`)**: This approach uses a single element type (e.g., `div`, `p`, etc.) to select elements.

**Pros and Cons of each approach**

1. **Class selectors (`class`)**:
	* Pros:
		+ More specific and flexible, as classes can be combined using multiple dots (e.g., `.hello .world`).
		+ Can be used to target elements with dynamic or attribute-based styles.
	* Cons:
		+ May lead to slower performance due to the need for more complex parsing and matching.
2. **Tag selectors (`tag`)**:
	* Pros:
		+ Faster performance, as the browser can use caching and optimization techniques.
		+ Easier to read and understand, especially for simple scenarios.
	* Cons:
		+ Less flexible, as it only selects elements of a specific type.
		+ May lead to more elements being matched accidentally.

**Other considerations**

1. **CSS Preprocessing**: When using class selectors, the browser may need to preprocess CSS rules before applying them, which can add overhead. In contrast, tag selectors typically don't require preprocessing.
2. **DOM Manipulation**: If you're manipulating or modifying elements in your JavaScript code, using a class selector might lead to additional DOM changes, which can slow down performance.

**Library usage**

None of the provided test cases use external libraries. However, if they did, it's likely that the library would provide functions for working with CSS selectors (e.g., `querySelector`, `querySelectorAll`).

**Special JS feature or syntax**

This benchmark does not explicitly test any special JavaScript features or syntax.

**Alternatives**

If you wanted to create a similar benchmark, you could consider adding more test cases, such as:

* Using attribute selectors (`[attribute]`)
* Combining class and tag selectors (e.g., `div.class` or `.class` followed by an element type)
* Testing performance with different number of elements or complexity

Keep in mind that the specific alternatives would depend on your goals and the scope of your benchmark.

To create a new benchmark, you can use tools like MeasureThat.net's API or write custom scripts to generate test cases. You can also explore other benchmarks and libraries, such as:

* JSPerf
* BrowserStack
* WebPageTest

These resources provide various ways to measure and compare performance in different browsers and environments.

Related benchmarks:

tag VS class (version: 0)

Comparing performance of: class vs tag

Created: one year ago by: Guest

Jump to the latest result

class

tag

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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