Toggle navigation
MeasureThat.net
Create a benchmark
Tools
Feedback
FAQ
Register
Log In
foobar-ccmpcp-4
(version: 0)
Comparing performance of:
querySelector vs querySelectorAll vs getElementsByTagName
Created:
7 years ago
by:
Guest
Jump to the latest result
HTML Preparation code:
<html> <head> </head> <body> <div id=''></div> </body> </html>
Tests:
querySelector
document.querySelector('body');
querySelectorAll
document.querySelectorAll('body');
getElementsByTagName
document.getElementsByTagName('body')[0];
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
Fork
Test case name
Result
querySelector
querySelectorAll
getElementsByTagName
Fastest:
N/A
Slowest:
N/A
Latest run results:
No previous run results
This benchmark does not have any results yet. Be the first one
to run it!
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net. **What is being tested?** The provided JSON represents three individual test cases that measure the performance of different methods for selecting DOM elements in JavaScript: 1. `document.querySelector('body')` 2. `document.querySelectorAll('body')` 3. `document.getElementsByTagName('body')[0]` These methods are used to retrieve a single or multiple HTML elements with a specific selector. **Options compared** The three options being compared are: * `querySelector`: A method that returns the first element matching the specified selector. * `querySelectorAll`: A method that returns a NodeList containing all elements matching the specified selector. * `getElementsByTagName`: A method that returns an HTMLCollection of all elements with the specified tag name. **Pros and Cons** Here's a brief summary of the pros and cons of each approach: 1. **querySelector**: * Pros: More efficient than `getElementsByTagName` since it only retrieves one element, reducing memory allocation and garbage collection overhead. * Cons: Returns only the first matching element, so if there are multiple elements, it will return the first one. 2. **querySelectorAll**: * Pros: Returns all matching elements, making it suitable for situations where you need to process a list of elements. * Cons: Can be slower than `querySelector` since it needs to allocate memory for a NodeList and iterate over its length. 3. **getElementsByTagName**: * Pros: Simple and widely supported, as it's part of the DOM API. * Cons: Inefficient compared to `querySelector`, especially when dealing with large documents or multiple elements. **Library usage** In this benchmark, none of the libraries are explicitly mentioned in the provided JSON data. However, JavaScript engines like V8 (used by Chrome) and SpiderMonkey (used by Firefox) provide built-in support for these DOM methods. **Special JS feature/syntax** None of the test cases use any special JavaScript features or syntax that would require additional explanation. **Other alternatives** If you're interested in exploring alternative approaches, here are a few: * `getElementsByClassName` and `getElementById` can be used as alternatives to `querySelector` and `querySelectorAll`, respectively. * Modern web browsers also provide newer methods like `document.querySelector(':has')` and `document.querySelectorAll(':has')` for more complex selectors. Keep in mind that these alternative approaches might have different performance characteristics, so it's essential to test them thoroughly if you suspect they would be better suited for your use case.
Related benchmarks:
DOM Selection
Selector Comparisons with Example Shop Data
querySelectorAll head vs unrestricted
innerText 2
Closest or loop
Comments
Confirm delete:
Do you really want to delete benchmark?