Benchmark: querySelector - MeasureThat.net

HTML Preparation code:

<div class="c1 c2 c3" id="fist-id">
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Script Preparation code:

x = 0;

Tests:

querySelector
let n = (Math.random() * 45) | 0; x = document.querySelector("#blahblah-" + n);
getElementById
let n = (Math.random() * 45) | 0; x = document.getElementById("blahblah-" + n);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelector
getElementById

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided benchmark measures the performance of two HTML query methods: `document.querySelector` and `document.getElementById`. The test cases involve randomly selecting elements with IDs containing a number between 0 and 45, which are generated using `Math.random() * 45 | 0`.

**Options Compared**

Two options are compared:

1. **`document.querySelector`**: This method uses a CSS selector to select the element(s) that match the specified query.
2. **`document.getElementById`**: This method directly accesses an element by its ID.

**Pros and Cons of Each Approach**

* `document.querySelector`:
	+ Pros:
		- More flexible and powerful, allowing for selection of multiple elements based on CSS selectors.
		- Can be used to select nested elements or elements with different class names.
	+ Cons:
		- May be slower than `document.getElementById` due to the need to parse CSS selectors.
* `document.getElementById`:
	+ Pros:
		- Faster and more efficient, as it directly accesses an element by its ID.
		- Simple and straightforward to use.
	+ Cons:
		- Less flexible and powerful, only allowing direct access to elements with unique IDs.

**Library Usage**

The benchmark uses the `document` object from the Document Object Model (DOM) library, which provides a way to interact with HTML documents programmatically. The `querySelector` method is an extension of the DOM API that allows for CSS selectors.

**Special JS Features or Syntax**

This benchmark does not use any special JavaScript features or syntax beyond what is required by the standard DOM APIs. No ES6+ features like async/await, classes, or template literals are used.

**Other Alternatives**

If you need to measure performance of other HTML query methods, here are some alternatives:

* `document.getElementsByTagName`: This method returns a list of elements that match the specified tag name.
* `document.querySelectorAll`: This method is similar to `querySelector`, but returns all matching elements instead of just one.

Note: These alternatives may have different performance characteristics and use cases compared to `document.querySelector` and `document.getElementById`.

Related benchmarks:

querySelector (version: 0)

Comparing performance of: querySelector vs getElementById

Created: 7 years ago by: Guest

Jump to the latest result

querySelector

getElementById

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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