Benchmark: My Test2 - MeasureThat.net

HTML Preparation code:

<div class='test'></div>

Tests:

ClassName
document.getElementsByClassName('test');
QuerySelector
document.querySelector('.test');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
ClassName
QuerySelector

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into the details of this benchmark.

**Benchmark Overview**

The benchmark measures the performance of two different methods for selecting HTML elements on a webpage: `document.getElementsByClassName()` and `document.querySelector()`. These methods are used to retrieve elements that match certain criteria, such as a specific CSS class or ID.

**Test Cases**

There are two test cases:

1. **ClassName**: This test uses `document.getElementsByClassName('test');`, which selects all HTML elements with the class 'test' on the webpage.
2. **QuerySelector**: This test uses `document.querySelector('.test');`, which is a more modern and concise method for selecting a single element that matches the given CSS selector.

**Benchmark Results**

The latest benchmark results show two different execution rates per second for each test case:

1. **ClassName**: 5441983.5 executions per second (using `getElementsByClassName`)
2. **QuerySelector**: 3090310.5 executions per second (using `querySelector`)

**Analysis and Comparison**

From the results, we can see that:

* The `document.getElementsByClassName()` method is significantly faster than the `document.querySelector()` method for selecting multiple elements with a specific class.
* However, when selecting a single element with a CSS selector, `document.querySelector()` performs slightly better.

**Pros and Cons of Each Method**

* `document.getElementsByClassName()`: This method is more efficient when selecting multiple elements with a specific class. It's also widely supported across different browsers. However, it may not be as concise or intuitive to use for complex selectors.
* `document.querySelector()`: This method provides a more modern and flexible way to select HTML elements using CSS selectors. It's ideal for selecting single elements or groups of elements using complex selectors. However, it may have performance implications when dealing with large numbers of elements.

**Other Considerations**

When choosing between these methods, consider the following:

* **Selector complexity**: If you're working with simple selectors (e.g., a specific class), `document.getElementsByClassName()` might be sufficient. For more complex selectors or single element selection, use `document.querySelector()`.
* **Performance sensitivity**: If performance is critical in your application, test both methods to determine which one works best for your specific use case.
* **Browser support**: Both methods are widely supported across modern browsers.

**Library and JavaScript Features Used**

No external libraries were used in this benchmark. The tests only rely on native JavaScript features.

**Alternatives**

Other alternatives for selecting HTML elements include:

1. `document.getElementById()`: Selects a single element based on its ID.
2. **CSS selectors**: Use CSS selectors directly to select elements, which can be more efficient and concise than using JavaScript methods.
3. **DOM traversal**: Manually traverse the DOM tree to find elements, which can be less efficient but provides fine-grained control.

Remember that performance differences may vary depending on your specific use case and browser versions.

Related benchmarks:

My Test2 (version: 0)

Comparing performance of: ClassName vs QuerySelector

Created: 7 years ago by: Guest

Jump to the latest result

ClassName

QuerySelector

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):