Benchmark: querySelector vs getElementBy

HTML Preparation code:

<h1 id="id"></h1>

Script Preparation code:

var n = []

Tests:

by
n.push(document.getElementById('id'))
query
n.push(document.querySelector('#id'))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
by
query

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 llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, along with the pros and cons of each approach.

**Benchmark Overview**

The benchmark compares two methods for retrieving an HTML element using JavaScript: `document.getElementById` (by) and `document.querySelector` (query). The goal is to determine which method is faster in various scenarios.

**Script Preparation Code**

The script preparation code initializes an empty array `n`. This variable will be used to store the execution results of both methods. For example, when running a test case like "by", `n.push(document.getElementById('id'))` would add a new element to the array.

**Html Preparation Code**

The HTML preparation code creates a simple webpage with a single `<h1>` element and an ID attribute set to `"id"`: `<h1 id="id"></h1>`. This element will be used as the target for both methods being compared.

**Test Cases**

There are two test cases:

1. "by" (using `document.getElementById`):
```javascript
n.push(document.getElementById('id'));
```
2. "query" (using `document.querySelector`):
```javascript
n.push(document.querySelector('#id'));
```
**Library: DOM Methods**

Both methods use the Document Object Model (DOM) to interact with the HTML document. Specifically, `document.getElementById` returns the element at the specified ID, while `document.querySelector` uses a CSS selector to match the element.

The purpose of these libraries is to provide a way for JavaScript code to access and manipulate the structure of an HTML document.

**Special JS Feature/Syntax: None**

There are no special features or syntax used in this benchmark. The focus is on comparing the performance of two existing methods.

**Other Alternatives**

If you're looking for alternatives to `document.getElementById` and `document.querySelector`, consider the following options:

1. **querySelectorAll**: Similar to `querySelector`, but returns all elements that match the CSS selector instead of just one.
2. **getAttribute()` and **getAttributeNames()**: Alternative methods for retrieving attribute values and iterating over attribute names, respectively.
3. **requestAnimationFrame()` and **setTimeout()`: For asynchronous operations, use these functions to schedule tasks without blocking the main thread.

In summary, this benchmark compares the performance of two common JavaScript methods for retrieving HTML elements: `document.getElementById` and `document.querySelector`. Understanding the pros and cons of each approach can help you make informed decisions about which method to use in your own code.

Related benchmarks:

querySelector vs getElementBy (version: 0)

Comparing performance of: by vs query

Created: 3 years ago by: Guest

Jump to the latest result

by

query

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):