Benchmark: getElementById vs getElementsByName

HTML Preparation code:

<div id="testdiv">
  <div id="unique" class="unique" name="unique" data-unique="1">test</div>
</div>

Script Preparation code:

var i, imax;
var doc = document;

Tests:

getElementById
var test = doc.getElementById('unique');
getElementsByName
var test = doc.getElementsByName('unique')[0]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById
getElementsByName

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
getElementById	47367068.0 Ops/sec
getElementsByName	21625008.0 Ops/sec

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!

**Benchmark Overview**

The MeasureThat.net benchmark measures the performance of two different approaches to retrieve a specific DOM element: `getElementById` and `getElementsByName`. The goal is to identify which approach is faster.

**Options Compared**

There are two options being compared:

1. **`getElementById`**: This method retrieves an element by its ID attribute. It's a common way to access elements in HTML documents.
2. **`getElementsByName`**: This method retrieves all elements that have a specific name attribute. In this case, it's searching for an element with the name "unique".

**Pros and Cons**

1. `getElementById`:
	* Pros: Fast and efficient, as it only searches for one element by ID.
	* Cons: May not be suitable when the element is not unique (e.g., multiple elements have the same ID), or when the element is dynamically generated with a unique ID.
2. `getElementsByName`:
	* Pros: Suitable when the element is not unique, as it can return all matching elements. However, this approach may be slower due to the need to search for multiple elements.
	* Cons: May be slower than `getElementById` when only one element needs to be retrieved.

**Library and Its Purpose**

In this benchmark, there is no explicit library being used, but we can assume that the JavaScript engine (e.g., V8 in Chrome) provides these two methods as part of its standard DOM API. The `getElementsByName` method may use a more complex algorithm under the hood to find matching elements.

**Special JS Feature or Syntax**

There is no special JavaScript feature or syntax being used in this benchmark. It's a simple comparison of two standard DOM methods.

**Other Alternatives**

If you need to retrieve an element by name, other alternatives might include:

* Using `querySelector` or `querySelectorAll` with CSS selectors
* Implementing a custom search algorithm using regular expressions or string matching
* Using a library like jQuery (although this benchmark doesn't use jQuery)

Keep in mind that the choice of method depends on the specific requirements of your application, such as performance, uniqueness, and dynamic element generation.

**Benchmark Preparation Code**

The provided `Script Preparation Code` sets up a variable `doc` to represent the HTML document object. The `Html Preparation Code` defines an HTML fragment with two elements: one with a unique ID (`testdiv`) and another with a unique name attribute (`unique`). This setup allows for easy access to both elements using the benchmarked methods.

I hope this explanation helps!

Related benchmarks:

getElementById vs getElementsByName (version: 0)

Test performance of different ways of get just one particular DOM element

Comparing performance of: getElementById vs getElementsByName

Created: 6 years ago by: Guest

Jump to the latest result

getElementById

getElementsByName

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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