Let's dive into the explanation of the provided benchmark.

What is being tested?

The benchmark compares two methods for selecting all elements with the tag name 'div' in an HTML document: querySelectorAll and getElementsByTagName.

Options compared

The two options are compared:

1. querySelectorAll: This method returns a NodeList, which is a live HTMLCollection of all elements that match the specified selector.
2. getElementsByTagName: This method also returns a collection of nodes (in this case, HTML elements), but it's an older and more traditional approach to selecting elements in DOM.

Pros and Cons

• querySelectorAll
  • Pros: More modern and efficient than getElementsByTagName, as it leverages the browser's CSS selector engine.
  • Cons: Requires Internet Explorer 9 or later for compatibility. Can be slower on older browsers.
• getElementsByTagName
  • Pros: More widely supported across older browsers, including Internet Explorer 8 and earlier.
  • Cons: Less efficient than querySelectorAll due to its reliance on the browser's built-in DOM implementation.

Library usage

Neither of these methods relies on a specific library, but they do utilize the Document Object Model (DOM) of HTML documents. The DOM provides an interface for manipulating and querying elements in an HTML document.

Special JavaScript features or syntax

None are mentioned in this benchmark.

Other alternatives

If you were to rewrite these benchmarks using more modern JavaScript features, you could use:

• Array.from() with a CSS selector: const allDivs = Array.from(document.querySelectorAll('div'));
• The Array.prototype.forEach method: document.querySelectorAll('div').forEach(function (div) { console.log(div); });

However, these alternatives are not directly comparable to the original querySelectorAll and getElementsByTagName methods.

Benchmark preparation code

The provided HTML preparation code creates a single-page document with 11 <div> elements. The script preparation codes for each test case select all <div> elements using their respective methods.

Latest benchmark result

The latest results show that querySelectorAll is slightly faster than getElementsByTagName, executing approximately 76,000 more times per second on the provided hardware configuration.