Benchmark: getElementById.getElementsByClassName vs getElementsByClassName vs getElementById.childNodes vs document.forms

HTML Preparation code:

<div id="header">
		<div id="logo">
			<img src="images/logo.png" alt="the network"/>
		</div>	
		<div id="search">
			<form method="get">
				<input type="text" name="post" placeholder="thoughts?"/>
				<input type="submit" value="Post">
			</form>
		</div>
	</div>
</div>	
<div id="page">
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
  <p>some message</p>
</div>

Tests:

getElementById.childNodes
var form = document.getElementById("search").childNodes[0];
getElementById.getElementsByTagName
var form = document.getElementById("search").getElementsByTagName("form")[0];
getElementsByTagName
var form = document.getElementsByTagName("form")[0];
document.forms[0]
var form = document.forms[0];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById.childNodes
getElementById.getElementsByTagName
getElementsByTagName
document.forms[0]

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested, the options compared, their pros and cons, and other considerations.

**Benchmark Definition**

The benchmark is defined by two main parts: "Description" and "Script Preparation Code". The description states that it's comparing `getElementById` with `getElementsByClassName`, while the script preparation code is empty, which means no JavaScript code is provided to set up the test environment.

However, individual test cases are provided in a separate list. These test cases compare different ways of accessing elements within an HTML document:

*   `document.getElementById("search").childNodes[0]`
*   `document.getElementById("search").getElementsByTagName("form")[0]`
*   `document.getElementsByTagName("form")[0]`
*   `document.forms[0]`

These test cases are comparing the performance of different methods to access elements in an HTML document.

**Options Compared**

The options compared in this benchmark are:

1.  **`document.getElementById("search").childNodes[0]"`: This method uses the `getElementById` method to get a reference to the element with the specified ID, and then accesses its first child node.
2.  `document.getElementById("search").getElementsByTagName("form")[0]`
    *   This method uses the `getElementById` method to get a reference to the element with the specified ID, and then uses the `getElementsByTagName` method to get an array of all elements with the specified tag name (in this case, "form"), and returns the first one.
3.  `document.getElementsByTagName("form")[0]`
    *   This method directly accesses all form elements in the HTML document using the `getElementsByTagName` method and returns the first one.
4.  `document.forms[0]`

**Pros and Cons**

Here's a brief summary of each option:

1.  **`document.getElementById("search").childNodes[0]"**: This method is simple and efficient, but it has some drawbacks:
    *   It only works if you know the exact ID of the element.
    *   It requires two calls to `getElementById` and then accessing a child node.

2.  `document.getElementById("search").getElementsByTagName("form")[0]`
    *   This method can work even when you don't have an ID for the element, but it's slower than `getElementById` and also returns all matching elements instead of just one.
3.  `document.getElementsByTagName("form")[0]`: This is generally considered the best option since it doesn't require any additional calls or knowledge about the element's properties.

**Other Considerations**

Here are a few additional considerations:

*   The `document.forms` property is only available in HTML documents with forms, and accessing elements via `document.forms` can be slower than other methods.
*   Using `getElementsByTagName` to get all matching elements can lead to unnecessary overhead if there's only one element that needs to be accessed.

**Alternatives**

Here are some alternative approaches:

1.  **Using a library like jQuery**: Libraries like jQuery often provide optimized and standardized ways of accessing elements, which might outperform native JavaScript methods.
2.  **Dom manipulation libraries like React or Angular**: If you're building complex UI applications, using a full-fledged library for DOM manipulation can be more efficient than manual DOM access.

Keep in mind that the choice of method depends on your specific requirements and the type of application you're developing.

Here's an example of how to write the individual test cases:

```javascript
// test case 1: getElementById.childNodes
function testGetElementByIdChildNodes() {
    const html = "<div id=\"search\"><form><input type=\"text\"></form></div>";
    var form = document.getElementById("search").childNodes[0];
}

// test case 2: getElementById.getElementsByTagName
function testGetElementByIdGetElementsByTagName() {
    const html = "<div id=\"search\"><form><input type=\"text\"></form></div>";
    var form = document.getElementById("search").getElementsByTagName("form")[0];
}

// test case 3: getElementsByTagName
function testGetElementsByTagName() {
    const html = "<div id=\"search\"><form><input type=\"text\"></form></div>";
    var form = document.getElementsByTagName("form")[0];
}

// test case 4: document.forms[0]
function testDocumentForms() {
    const html = "<div id=\"search\"><form><input type=\"text\"></form></div>";
    var form = document.forms[0];
}
```

Note that these examples assume you have a basic understanding of JavaScript and DOM manipulation.

Latest run results:

Run details: (Test run date: 5 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36 OPR/62.0.3331.72

Browser/OS: Opera 62 on Windows

View result in a separate tab

Test name	Executions per second
getElementById.childNodes	1436141.5 Ops/sec
getElementById.getElementsByTagName	1103667.9 Ops/sec
getElementsByTagName	1285066.0 Ops/sec
document.forms[0]	1093051.2 Ops/sec

Related benchmarks:

getElementById.getElementsByClassName vs getElementsByClassName vs getElementById.childNodes vs document.forms (version: 0)

getElementById vs getElementsByClassName

Comparing performance of: getElementById.childNodes vs getElementById.getElementsByTagName vs getElementsByTagName vs document.forms[0]

Created: 5 years ago by: Guest

Jump to the latest result

getElementById.childNodes

getElementById.getElementsByTagName

getElementsByTagName

document.forms[0]

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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