Toggle navigation
MeasureThat
.net
Create a benchmark
Tools
Feedback
Feature Requests
FAQ
Register
Log In
Direct querySelector scope vs no scope
(version: 0)
Benchmark.js
Comparing performance of:
querySelector scope vs querySelector no scope
Created:
2 years ago
by:
Guest
Go to the latest result
HTML Preparation code:
<div id='parent'> <div class="foo"> <div class="bar"> <div class="baz"> </div> </div> </div> </div>
Tests:
querySelector scope
document.getElementById("parent").querySelector(':scope > .foo')
querySelector no scope
document.getElementById("parent").querySelector('.foo')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
querySelector scope
querySelector no scope
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36
Browser/OS:
Chrome 134 on Windows
View result in a separate tab
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=592589" width="100%" height="500px"></iframe>
querySelector no scope
3.2M/s
querySelector scope
2.2M/s
View exact numbers
Test name
Executions per second
✓
querySelector no scope
3,189,146 Ops/sec
querySelector scope
2,153,085 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what's being tested, the options compared, pros and cons of those approaches, and other considerations. **Benchmark Overview** The provided benchmark tests two different approaches for selecting elements in HTML using `querySelector`. The test consists of: 1. A parent element (`<div id="parent">`) containing multiple child elements (`<div class="foo">`, `<div class="bar">`, and `<div class="baz">`). 2. Two individual test cases: * `querySelector scope`: Selects the `.foo` element inside the current scope of the query (i.e., the same scope as the parent element). * `querySelector no scope`: Does not consider the current scope, resulting in a slower performance. **Options Compared** The two options being compared are: 1. **Selector scope**: The query selector engine uses the element's scope to optimize the lookup process. In this case, it looks for elements inside the parent element. 2. **No scope**: The query selector engine does not consider the current scope, resulting in a slower performance. **Pros and Cons** * **Selector scope (with scope)**: + Pros: Faster performance since the engine can optimize the lookup process using the element's scope. + Cons: May not work as expected if the DOM is modified dynamically or if the `:scope` pseudo-class is not supported in certain browsers. * **No scope**: + Pros: Works consistently even when the DOM is modified dynamically, but may incur a performance penalty due to slower lookup. + Cons: Less optimized performance compared to using the selector scope. **Library and Purpose** There is no library being used in this benchmark. However, it's worth noting that `querySelector` is a standard querySelector API function provided by modern browsers. **Special JS Feature/Syntax** None of the test cases use special JavaScript features or syntax beyond the standard HTML5 DOM APIs.
Related benchmarks
getElementsByClassName()[0] vs querySelectorAll
JQuery: find vs selector vs scoped selector - More Html
element.children vs element.querySelectorAll vs element.querySelectorAll(:scope)
Comments
Confirm delete:
Do you really want to delete benchmark?