Toggle navigation
MeasureThat
.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
querySelector vs getElementsByClassName fixed?
(version: 0)
Comparing performance of:
querySelector vs getElementsByClassName
Created:
2 years ago
by:
Guest
Go to the latest result
HTML Preparation code:
<div class="test"></div>
Tests:
querySelector
document.querySelector(".test")
getElementsByClassName
document.getElementsByClassName("test")
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
querySelector
getElementsByClassName
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:124.0) Gecko/20100101 Firefox/124.0
Browser/OS:
Firefox 124 on Windows
View result in a separate tab
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=519860" width="100%" height="500px"></iframe>
getElementsByClassName
9.6M/s
querySelector
4.7M/s
View exact numbers
Test name
Executions per second
✓
getElementsByClassName
9,596,058 Ops/sec
querySelector
4,703,526 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and its test cases to understand what's being tested. **Benchmark Definition JSON** The benchmark definition is represented by the following JSON: ``` { "Name": "querySelector vs getElementsByClassName fixed?", "Description": null, "Script Preparation Code": null, "Html Preparation Code": "<div class=\"test\"></div>" } ``` This benchmark is testing the performance difference between two DOM query methods: `document.querySelector()` and `document.getElementsByClassName()`. The `Html Preparation Code` specifies a simple HTML element (`<div class="test"></div>`) that will be used as the target for the queries. **Test Cases** The individual test cases are defined in the following JSON: ``` [ { "Benchmark Definition": "document.querySelector(\".test\")", "Test Name": "querySelector" }, { "Benchmark Definition": "document.getElementsByClassName(\"test\")", "Test Name": "getElementsByClassName" } ] ``` Each test case is defined by a `Benchmark Definition` (a JavaScript expression that uses the target HTML element) and a corresponding `Test Name`. **Library and Purpose** Both test cases use the DOM API, which is part of the browser's core functionality. The DOM API provides methods for interacting with an HTML document, such as querying elements. **JavaScript Features and Syntax** Neither of the test cases explicitly uses any special JavaScript features or syntax beyond the standard DOM API methods. **Comparison Options** The two comparison options are: 1. `document.querySelector()`: This method returns a single element that matches the specified selector (in this case, `.test`). 2. `document.getElementsByClassName()` : This method returns a live HTMLCollection of all elements with the specified class name (in this case, `test`). **Pros and Cons** Here's a brief overview of each option: * `document.querySelector()`: Pros: + Faster performance, as it only searches for one element. + Can be more efficient when dealing with small sets of elements. + Returns a single result, which can be useful in certain scenarios. * Cons: + May not find all matching elements if there are multiple elements with the same class name. * `document.getElementsByClassName()` : Pros: + Finds all matching elements, which can be useful when dealing with large sets of elements. + Returns a live HTMLCollection, allowing for further iteration and manipulation. + Can handle elements with different class names, not just the exact match. * Cons: + May be slower performance due to the need to search multiple elements. + Returns all matching elements, which can lead to more complex code. **Other Considerations** The choice between `document.querySelector()` and `document.getElementsByClassName()` depends on the specific use case. If you're dealing with a small set of elements and want a faster, more efficient solution, `querySelector` might be a better choice. However, if you need to find multiple elements or handle different class names, `getElementsByClassName` is likely a better option. **Alternative Approaches** Other alternatives for querying DOM elements include: * Using CSS selectors (e.g., `.test`) * Using regular expressions (e.g., `/test/`) * Using query libraries like jQuery Keep in mind that each alternative has its own trade-offs and may not offer the same performance or functionality as `document.querySelector()` or `document.getElementsByClassName()`.
Related benchmarks
querySelector() vs getElementsByClassName()[0]
getElementsByClassName()[0] vs querySelectorAll
querySelector vs getElementsByClassName My
Comments
Confirm delete:
Do you really want to delete benchmark?