Benchmark: getElementById vs querySelector２

HTML Preparation code:

<div id="testElement2">You can't do it with the strike tag OR the text-decoration:line-through style. The line position is built-in. You could roll your own style for that, but it would be a huge PITA.</div>
<div id="testElement12"></div>
<div id="testElement"></div>
<div>
  <div id="testElement4"><button></button></div>
<div id="testElement5"></div>
</div>
<div id="testElement6"></div>
<div id="testElement7">You can't do it with the strike tag OR the text-decoration:line-through style. The line position is built-in. You could roll your own style for that, but it would be a huge PITA.</div>
<div id="testElement8"></div>
<div id="testElement9"></div>

Tests:

getElementById
var el = document.getElementById('testElement'); var className = el.className;
querySelector
var el = document.querySelector('#testElement'); var className = el.className;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
getElementById
querySelector

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:122.0) Gecko/20100101 Firefox/122.0

Browser/OS: Firefox 122 on Windows

View result in a separate tab

Test name	Executions per second
getElementById	9237728.0 Ops/sec
querySelector	4322403.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark measures the performance difference between two JavaScript methods: `document.getElementById` and `document.querySelector`. The test compares these two approaches to retrieve an element's class name.

**What is tested?**

* `document.getElementById`: A traditional method to select an element by its ID.
* `document.querySelector`: A more modern method to select elements based on a CSS selector or attribute.

**Options compared**

The benchmark compares the performance of `getElementById` and `querySelector`. These methods differ in their approach:

* `getElementById`: Directly searches for an element by its ID, which is typically unique.
* `querySelector`: Searches for an element that matches a given CSS selector or attribute. This method returns multiple elements if there are multiple matches.

**Pros and Cons**

* `getElementById`:
	+ Pros: Fast, reliable, and widely supported.
	+ Cons: Can be slow if the ID is not unique (e.g., when used with multiple elements having the same ID).
* `querySelector`:
	+ Pros: Flexible and powerful for complex selectors or attributes.
	+ Cons: May return multiple matches, which can lead to slower performance.

**Library and purpose**

There are no libraries mentioned in this benchmark. Both `document.getElementById` and `document.querySelector` are built-in methods of the Document Object Model (DOM) in JavaScript.

**Special JS features or syntax**

No special JavaScript features or syntax are used in these test cases. The focus is solely on comparing the performance of two DOM-related methods.

**Other alternatives**

If you're interested in exploring alternative approaches, consider:

* `document.getElementsByTagName`: Retrieves a list of all elements matching a given tag name.
* `document.querySelectorAll`: A more powerful version of `querySelector` that returns all matches from a single selector string.

Keep in mind that these alternatives might have different performance characteristics compared to the original methods tested in this benchmark.

Related benchmarks:

getElementById vs querySelector２ (version: 0)

Comparing performance of: getElementById vs querySelector

Created: 2 years ago by: Guest

Jump to the latest result

getElementById

querySelector

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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