Benchmark: class vs id test 3

HTML Preparation code:

<div id="id1" class="cl2">
  <span>some text</span>
</div>

Tests:

id
document.getElementById("id1");
class
document.querySelector(".cl2");

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
id
class

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):

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Let's break down what's being tested and compared in this benchmark.

**Benchmark Description**

The benchmark is called "class vs id test 3". It compares two ways of selecting an HTML element using JavaScript:

1. `document.getElementById("id1");`
2. `document.querySelector(".cl2");`

**Test Cases**

There are two individual test cases:

1. **"id"**: This test case uses the method `document.getElementById("id1");` to select an HTML element.
	* Library: None (built-in JavaScript API)
	* Special JS feature or syntax: None
	* Purpose: This method is used to retrieve an HTML element by its ID attribute.
2. **"class"**: This test case uses the method `document.querySelector(".cl2");` to select an HTML element.
	* Library: None (built-in JavaScript API)
	* Special JS feature or syntax: `querySelector()` and CSS selector syntax
	* Purpose: This method is used to retrieve an HTML element by its class attribute.

**Comparison**

The benchmark measures the execution time per second for each test case. The results show that:

* The "id" test case has a higher execution rate (8,330,404 executions per second) than the "class" test case (5,009,300 executions per second).
* This suggests that selecting an element by ID is faster than selecting it by class.

**Pros and Cons**

Here's a brief summary of each approach:

1. **`document.getElementById()`**
	* Pros: Faster execution time, better performance for large documents.
	* Cons: Only retrieves one element with the specified ID.
2. **`document.querySelector()`**
	* Pros: Can retrieve multiple elements that match the CSS selector, flexible and powerful syntax.
	* Cons: Slower execution time compared to `getElementById()`, can be less efficient for large documents.

**Other Alternatives**

If you need to select an HTML element by its class attribute, you can use other methods:

1. **`document.getElementsByClassName()`**: Returns a list of elements with the specified class name.
2. **`querySelectorAll()`**: Similar to `querySelector()`, but returns a NodeList of matching elements.

Keep in mind that these alternatives might have different performance characteristics and are not directly compared in this benchmark.

Related benchmarks:

class vs id test 3 (version: 0)

Comparing performance of: id vs class

Created: 3 years ago by: Guest

Jump to the latest result

id

class

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.1:latest, generated one year ago):