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querySelector vs getElementByTagName
(version: 0)
Comparing performance of:
querySelector vs getElementByTagName
Created:
4 years ago
by:
Guest
Go to the latest result
HTML Preparation code:
<div><span></span></div>
Tests:
querySelector
document.querySelector('span')
getElementByTagName
document.getElementsByTagName('span')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
querySelector
getElementByTagName
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
5 months ago
)
User agent:
Mozilla/5.0 (X11; Linux x86_64; rv:147.0) Gecko/20100101 Firefox/147.0
Browser/OS:
Firefox 147 on Linux
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=625232" width="100%" height="500px"></iframe>
getElementByTagName
4.4M/s
querySelector
1.7M/s
View exact numbers
Test name
Executions per second
✓
getElementByTagName
4,359,707 Ops/sec
querySelector
1,674,115 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks. **What is tested?** The provided JSON benchmark tests two different methods to retrieve an element from a HTML document: `document.querySelector` and `document.getElementsByTagName`. The benchmarks aim to compare the performance of these two approaches. **Options being compared** * **querySelector**: A method introduced in ECMAScript 5 (2009) that allows selecting elements using CSS selectors. * **getElementsByTagName**: A traditional method that returns a collection of all elements with the specified tag name. **Pros and Cons of each approach:** ### QuerySelector Pros: 1. **Flexibility**: Allows selecting elements based on their class, id, attributes, or CSS properties, making it more versatile than `getElementsByTagName`. 2. **Readability**: Can be more readable when writing code since it's often easier to understand the intent behind a CSS selector. 3. **Performance**: Generally faster than `getElementsByTagName`, as it uses a single DOM query that can return multiple results. Cons: 1. **Browser Support**: Not supported in older browsers (pre-ECMAScript 5). 2. **Complexity**: Can be more challenging to maintain, especially for complex selectors or scenarios where the element may not exist. ### GetElementsByTagName Pros: 1. **Browser Support**: Works across all major browsers and versions. 2. **Simple**: Easy to implement and understand, as it's a straightforward method that returns an array of elements with the specified tag name. Cons: 1. **Performance**: Typically slower than `querySelector`, especially when dealing with large datasets or complex queries. **Library usage** None of the provided benchmarks use any external libraries for their test cases. **Special JS features or syntax** There's no special JavaScript feature or syntax used in these benchmark definitions, as they only focus on comparing the performance of basic DOM query methods (`querySelector` and `getElementsByTagName`).
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