Benchmark: querySelectorAll vs getElementsByTagName ES6 iteration

HTML Preparation code:

<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>

Tests:

querySelectorAll
const allDivs = [...document.querySelectorAll('div')]; allDivs.forEach(function (div) {});
getElementsByTagName
const allDivs = [...document.getElementsByTagName('div')]; allDivs.forEach(function (div) {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
querySelectorAll
getElementsByTagName

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is tested, compared options, pros and cons, library usage, special JS features, and other considerations.

**Benchmark Overview**

The MeasureThat.net benchmark compares two methods to retrieve all `<div>` elements in an HTML document: `querySelectorAll` (ES6) and `getElementsByTagName`. The test generates a page with multiple `<div>` elements and measures the execution time of each method.

**Test Case Comparison**

The test case consists of two individual tests:

1. **`querySelectorAll`**: This test uses the modern JavaScript method to select all `<div>` elements using the `document.querySelectorAll` function, followed by iterating over the results with a `forEach` loop.
2. **`getElementsByTagName`**: This test uses the older DOM API method to retrieve all `<div>` elements using the `document.getElementsByTagName` function, also followed by iterating over the results with a `forEach` loop.

**Comparison Options**

The two methods have different approaches:

*   **`querySelectorAll` (ES6)**:
    *   Advantages:
        *   Faster execution time due to optimized native code
        *   More concise and readable syntax
        *   Suitable for modern JavaScript environments
    *   Disadvantages:
        *   Not supported in older browsers or Node.js versions
*   **`getElementsByTagName` (DOM API)**:
    *   Advantages:
        *   Supported in all browsers, including older ones
        *   Simple and familiar syntax
    *   Disadvantages:
        *   Slower execution time due to interpreted JavaScript code

**Other Considerations**

When choosing between these two methods, consider the following factors:

*   **Browser Support**: If you need to support older browsers, `getElementsByTagName` is a safer choice. However, if you're targeting modern browsers, `querySelectorAll` (ES6) might be more suitable.
*   **Performance**: If speed is critical, use `querySelectorAll` (ES6). Otherwise, the difference in execution time may not be significant enough to justify the complexity of using ES6 syntax.
*   **Readability and Maintainability**: Choose the method with the most concise and readable code. In this case, `querySelectorAll` (ES6) is often preferred due to its simplicity and modern syntax.

**Library Usage**

In neither test case does a library explicitly get used

Related benchmarks:

querySelectorAll vs getElementsByTagName ES6 iteration (version: 0)

Comparing performance of: querySelectorAll vs getElementsByTagName

Created: 2 years ago by: Guest

Jump to the latest result

querySelectorAll

getElementsByTagName

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):