Overview of the Benchmark

MeasureThat.net is a website where users can create and run JavaScript microbenchmarks to compare the performance of different approaches. The provided benchmark measures the performance of creating and cloning img elements in Firefox 80.

Script Preparation Code Analysis

The script preparation code defines a function makeImage(src) that creates an img element with the specified source URL. If src is truthy, it sets the src attribute of the img element to a base64-encoded GIF image. The function returns the created img element.

There are two variants of this function:

• makeImage(true) creates an img element with a non-empty source URL.
• makeImage(false) creates an empty img element without a source URL.

Options Comparison

The benchmark compares the performance of three approaches:

1. Creating an image with a source URL (create with src): This approach involves calling makeImage(true).
2. Creating an image without a source URL (creation without src): This approach involves calling makeImage(false).
3. Cloning an image and then setting the source URL (clone without src then set src): This approach involves cloning the result of makeImage(false) using the cloneNode() method, and then setting the src attribute to a base64-encoded GIF image.

Pros and Cons of Each Approach

1. Creating an image with a source URL:
   • Pros: May be faster due to reduced overhead of cloning.
   • Cons: Requires a non-empty source URL, which may not always be available.
2. Creating an image without a source URL:
   • Pros: Faster and more efficient, as it avoids the overhead of setting the src attribute.
   • Cons: Creates an empty img element, which may not be desirable in some cases.
3. Cloning an image and then setting the source URL:
   • Pros: Allows for more flexibility, as the cloned image can be used without modifying its attributes.
   • Cons: Slower due to cloning and then modifying the image.

Library and Special JS Features

The benchmark uses the cloneNode() method, which is a built-in JavaScript method that creates a deep copy of an element.

No special JS features or syntax are used in this benchmark.

Other Alternatives

If you wanted to modify the benchmark to compare other approaches, here are some alternatives:

• Compare the performance of using different image formats (e.g., JPEG, PNG) instead of GIF.
• Measure the performance of creating and cloning img elements in different browsers or versions.
• Add more complex scenarios, such as creating multiple images with different source URLs and then combining them into a single image.

These modifications would require additional script preparation code, test case definitions, and benchmark analysis.