Benchmark: body vs querySelector

HTML Preparation code:

<!doctype html>

<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">

  <title>A Basic HTML5 Template</title>
  <meta name="description" content="A simple HTML5 Template for new projects.">
  <meta name="author" content="SitePoint">

  <meta property="og:title" content="A Basic HTML5 Template">
  <meta property="og:type" content="website">
  <meta property="og:url" content="https://www.sitepoint.com/a-basic-html5-template/">
  <meta property="og:description" content="A simple HTML5 Template for new projects.">
  <meta property="og:image" content="image.png">

  <link rel="icon" href="/favicon.ico">
  <link rel="icon" href="/favicon.svg" type="image/svg+xml">
  <link rel="apple-touch-icon" href="/apple-touch-icon.png">

  <link rel="stylesheet" href="css/styles.css?v=1.0">

</head>

<body>
  <!-- your content here... -->
  <script src="js/scripts.js"></script>
</body>
</html>

Tests:

document.body
document.body
querySelector
document.querySelector('body')
getElementsByTagName
document.getElementsByTagName('body')[0]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
document.body
querySelector
getElementsByTagName

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 dive into the world of JavaScript microbenchmarks!

**What is being tested?**

The provided JSON represents two benchmark test cases:

1. `document.body`
2. `document.querySelector('body')`
3. `document.getElementsByTagName('body')[0]`

These three test cases are comparing different ways to access the `<body>` element in an HTML document.

**Options compared:**

* `document.body`: A straightforward way to access the `<body>` element using the DOM API.
* `document.querySelector('body')`: A more flexible approach that allows searching for elements by CSS selectors. In this case, it's used to select the first `<body>` element on the page.
* `document.getElementsByTagName('body')[0]`: An older method that uses the `getElementsByTagName` function to retrieve an array of all `<body>` elements and then returns the first one.

**Pros and cons of each approach:**

1. **`document.body`**:
	* Pros: Simple, efficient, and widely supported.
	* Cons: May not work if there are multiple `<body>` elements on the page (although this is unlikely in modern web development).
2. **`document.querySelector('body')`**:
	* Pros: Flexible, allowing for more complex CSS selectors. Can be used to select other elements or attributes.
	* Cons: May be slower than `document.body` due to the complexity of CSS selector parsing and execution. Also, may not work if there are no `<body>` elements on the page.
3. **`document.getElementsByTagName('body')[0]`**:
	* Pros: Works even if there are multiple `<body>` elements, as it returns an array with at least one element.
	* Cons: Less efficient than `document.body` and potentially slower due to the need to iterate over the array of results.

**Libraries and special JS features:**

There is no specific library mentioned in the provided code. However, note that `querySelectorAll` is a part of the W3C DOM Standard (2004) and has been supported by most modern browsers since then.

If you wanted to use a library for this benchmark, you could consider using a library like jQuery (which uses CSS selectors internally) or another similar library.

**Special JS features:**

There are no special JavaScript features mentioned in the provided code. However, if you're interested in exploring other approaches, some modern browsers support additional DOM methods and APIs that might be relevant to this benchmark.

**Alternatives:**

If you wanted to explore different approaches, here are a few alternatives:

* Use `document.createElement('body')` instead of `document.body`. This would create a new `<body>` element on the fly, which could potentially affect performance.
* Compare using `querySelectorAll` (if supported) or `getElementsByClassName` with CSS class names.
* Experiment with different HTML structures and content to see how they affect the benchmark results.

Keep in mind that these alternative approaches might not be as straightforward or widely supported as the original methods, so proceed with caution!

Related benchmarks:

body vs querySelector (version: 0)

Comparing performance of: document.body vs querySelector vs getElementsByTagName

Created: 3 years ago by: Guest

Jump to the latest result

document.body

querySelector

getElementsByTagName

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):