<html><head> <title>A Meaningful Page Title</title></head><body> The content of the document......</body></html>document.querySelector("head")document.getElementsByTagName("head")[0]--enable-precise-memory-info flag.
| Test case name | Result |
|---|---|
| querySelector | |
| getElementsByTagName |
| Test name | Executions per second |
|---|---|
| querySelector | 8998708.0 Ops/sec |
| getElementsByTagName | 7452778.0 Ops/sec |
Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net!
Benchmark Definition
The provided benchmark definition defines two test cases: querySelector and getElementsByTagName[0]. The benchmark is designed to compare the performance of these two methods for accessing an HTML element by its ID or name.
Options Compared
The two options being compared are:
document.querySelector("head"): This method uses the querySelector() function to select the first element that matches the specified CSS selector. In this case, it's searching for an element with the tag name "head".document.getElementsByTagName("head")[0]: This method uses the getElementsByTagName() function to retrieve all elements with the specified tag name and returns the first one.Pros and Cons
Here are some pros and cons of each approach:
querySelector:getElementsByTagName for simple queries.getElementsByTagName:Library and Purpose
There is no specific library mentioned in this benchmark. However, both querySelector() and getElementsByTagName() are part of the DOM (Document Object Model) API, which is a set of APIs for manipulating HTML documents.
Special JS Feature or Syntax
There is no special JavaScript feature or syntax used in this benchmark. The focus is on comparing two basic methods for accessing HTML elements.
Other Alternatives
If you're interested in exploring other alternatives, here are some options:
document.getElementById("head"): This method uses the getElementById() function to retrieve an element by its ID.document.querySelector("#head"): This method uses the querySelector() function to select an element with a specific CSS selector that includes an ID.document.querySelector("div.head"): This method uses the querySelector() function to select an element with a specific CSS selector that matches a tag name and attribute.Keep in mind that these alternatives may have different performance characteristics depending on the specific use case.
Benchmark Preparation Code
The provided HTML preparation code creates a simple HTML document with a <head> element. The script preparation code is empty, which means no JavaScript code is executed before running the benchmark.
I hope this explanation helps!
