Benchmark: querySelect - MeasureThat.net

Script Preparation code:

document.body.innerHTML = "<html><div>Hello World</div><div>second div</div><div>third div</div></html>";

Tests:

querySelector
document.querySelector("div")
querySelectorAll
document.querySelectorAll("div")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelector
querySelectorAll

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
querySelector	5562342.0 Ops/sec
querySelectorAll	2461398.8 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 provided JSON and explain what's being tested.

**Benchmark Definition**

The benchmark definition is a simple JavaScript expression that tests two different methods of selecting HTML elements: `document.querySelector` and `document.querySelectorAll`. The expressions are:

1. `document.querySelector("div")`: This method returns the first element in the DOM that matches the specified CSS selector (`"div"`). If no matching element is found, it returns `null`.
2. `document.querySelectorAll("div")`: This method returns a NodeList of all elements in the DOM that match the specified CSS selector (`"div"`).

**Options Compared**

The benchmark compares two options:

1. **Using `querySelector`**: This approach uses the `querySelector` method to select individual elements. It's faster for cases where only one element is expected.
2. **Using `querySelectorAll`**: This approach uses the `querySelectorAll` method to select multiple elements at once. It's slower for large datasets, but can be beneficial when dealing with a specific set of elements.

**Pros and Cons**

* **Using `querySelector`**:
	+ Pros: Faster execution time, better suited for small datasets.
	+ Cons: May not work as expected if the first element is not found (returns `null`), which can lead to unexpected behavior in subsequent code.
* **Using `querySelectorAll`**:
	+ Pros: More efficient when dealing with large datasets, returns a NodeList of all matching elements, and handles cases where no elements are found.
	+ Cons: Slower execution time compared to `querySelector`, may require additional processing if multiple elements need to be accessed.

**Library and Purpose**

The `document` object is part of the DOM (Document Object Model), which represents the structure of an HTML document. The `querySelector` and `querySelectorAll` methods are built-in browser APIs that provide a convenient way to traverse and manipulate the DOM.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax used in this benchmark.

**Other Alternatives**

If you need to select elements using alternative methods, consider:

* Using CSS selectors: You can use CSS selectors like `div` or `.class`, which work similarly to `querySelector`.
* Using `getElementsByClassName`: This method returns a collection of elements with the specified class name.
* Using `getElementsByTagName`: This method returns an array of elements with the specified tag name.

Keep in mind that each approach has its own trade-offs and may not always be the best choice for your specific use case.

Related benchmarks:

querySelect (version: 0)

Comparing performance of: querySelector vs querySelectorAll

Created: 2 years ago by: Guest

Jump to the latest result

querySelector

querySelectorAll

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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