Benchmark: Get elements by tag and class, vs. only tag, vs. only class

Get elements by tag and class, vs. only tag, vs. only class (version: 0)

Get elements by tag and class, vs. only tag, vs. only class. With querySelectorAll, getElementsByClassName, and getElementsByTagName.

Comparing performance of: querySelectorAll tag & class vs querySelectorAll only tag vs querySelectorAll only class vs getElementsByClassName vs getElementsByTagName

Created: 5 years ago by: Registered User

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HTML Preparation code:

<span class="span">1</span>
<span class="span">2</span>
<span class="span">3</span>
<span class="span">4</span>
<span class="span">5</span>

Tests:

querySelectorAll tag & class
document.querySelectorAll('span.span')
querySelectorAll only tag
document.querySelectorAll('span')
querySelectorAll only class
document.querySelectorAll('.span')
getElementsByClassName
document.getElementsByClassName('span')
getElementsByTagName
document.getElementsByClassName('span')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelectorAll tag & class
querySelectorAll only tag
querySelectorAll only class
getElementsByClassName
getElementsByTagName

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.

Let's break down the provided benchmark and its test cases.

**What is being tested?**

The benchmark tests three different ways to select HTML elements in JavaScript:

1. `querySelectorAll`: This method returns a NodeList of all elements that match the specified CSS selector.
2. `getElementsByClassName`: This method returns an array of all elements that have the specified class attribute value.
3. `getElementsByTagName`: This method returns an array of all elements with the specified tag name.

The benchmark measures how fast each of these methods is to execute on a specific set of HTML elements (span elements with the "span" class).

**Options compared**

The three options are being compared in terms of their execution speed:

* `querySelectorAll`: This option uses a CSS selector to match elements.
* `getElementsByClassName`: This option uses a class attribute value to match elements.
* `getElementsByTagName`: This option uses the tag name attribute to match elements.

**Pros and cons**

Here's a brief summary of each option's pros and cons:

* `querySelectorAll`:
	+ Pros: Fast, flexible, and powerful. It can be used to select elements based on various CSS selectors, including classes, IDs, attributes, etc.
	+ Cons: Can be slow if the selector is complex or matches many elements.
* `getElementsByClassName`:
	+ Pros: Simple, fast, and easy to use. It's specifically designed for selecting elements by class attribute value.
	+ Cons: Limited to matching elements with a specific class attribute value. Not as flexible as `querySelectorAll`.
* `getElementsByTagName`:
	+ Pros: Fast, simple, and easy to use. It's specifically designed for selecting elements by tag name.
	+ Cons: Limited to matching elements with a specific tag name. Not as flexible as `querySelectorAll`.

**Library and its purpose**

In this benchmark, the `querySelectorAll`, `getElementsByClassName`, and `getElementsByTagName` methods are part of the HTML DOM (Document Object Model) API. These methods allow JavaScript code to interact with and select elements within an HTML document.

**Special JS feature or syntax**

There is no special JS feature or syntax mentioned in the provided benchmark. The focus is on comparing the execution speed of three different method options.

**Other alternatives**

If you're looking for alternative ways to select elements in JavaScript, here are a few examples:

* Using jQuery (a popular JavaScript library): `$(`selector`).`
* Using CSS selectors with `document.querySelector()` or `document.querySelectorAll()`: `[selector]` or `[selector].`
* Using attribute-based selection: `document.evaluate('select([attribute])', document, null, XPathResult.ANY_TYPE, null).iterateNext().nodeValue;`

Keep in mind that these alternatives may have different performance characteristics and usage scenarios compared to the methods tested in this benchmark.

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