Benchmark: String head vs legit head

HTML Preparation code:

<script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-3.1.0.min.js"></script>

Script Preparation code:

//Add 100,000 elements
var frag = document.createDocumentFragment();
for (var i=0; i<10; i++){
  var outDiv = document.createElement('div');
  for (var j=0; j<100; j++){
    var midDiv = document.createElement('div');
    for (var k=0; k<100; k++){
      var inDiv = document.createElement('div');
      if(i==6 && j==60){
        if(k==60)
          inDiv.id="one";
        else if(k==61)
          inDiv.id="two";
      }
      midDiv.appendChild(inDiv)
    }
    outDiv.appendChild(midDiv)
  }
  frag.appendChild(outDiv);
}
document.body.appendChild(frag);

Tests:

String selector
if ($("head").length != 1) throw Error();
No selector
if ($(document.head).length != 1) throw Error();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String selector
No selector

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Measuring the performance of JavaScript microbenchmarks can be a complex task, and understanding what's being tested is crucial to interpreting the results.

**Benchmark Definition**

The provided JSON represents a benchmark that tests two different approaches for selecting the `head` element in an HTML document. There are three test cases:

1. **"String selector"**: This test case uses the string-based selector syntax `($("head").length != 1) throw Error();`. It checks if the length of the `head` element is equal to 1.
2. **"No selector"**: This test case uses a non-selectors-based approach `($(document.head).length != 1) throw Error();`, which targets the `head` element directly using the `document.head` property.

**Options Compared**

The two approaches compared are:

* String-based selector syntax (`$("head")`)
* Non-selector-based approach (`document.head`)

**Pros and Cons**

String-based selector syntax has some advantages over non-selectors-based approaches:

Pros:

* More concise and expressive syntax
* Allows for more complex selections using attribute filters, pseudo-classes, and more

Cons:

* Can be slower due to the additional overhead of parsing and executing the selector string
* May not be supported by older browsers or versions of jQuery

Non-selector-based approach has some advantages over string-based selectors:

Pros:

* Faster execution time, as it directly accesses the `head` property without the overhead of parsing a selector string
* More predictable performance, as the execution time is not dependent on the complexity of the selector

Cons:

* Less concise and expressive syntax
* May require more code to achieve the same functionality

**Library: jQuery**

The benchmark uses jQuery, a popular JavaScript library that provides a simplified way to interact with HTML documents. In this case, the `($)()` function is used as a shortcut for selecting elements using CSS selectors.

jQuery's purpose is to simplify DOM manipulation and event handling by providing a consistent and efficient API for working with HTML documents.

**Special JS Feature: None**

There are no special JavaScript features or syntaxes being tested in this benchmark. The tests focus on the performance differences between two different approaches to selecting the `head` element.

**Alternatives**

Other alternatives to string-based selectors or non-selector-based approaches include:

* CSS Selectors: Using pure CSS selectors (e.g., `head`) can provide similar performance benefits as the non-selector-based approach.
* Sizzle.js: A lightweight alternative to jQuery that provides a fast and efficient way to select elements using CSS selectors.
* Vanilla JavaScript: Using vanilla JavaScript functions like `getElementsByClassName()` or `querySelectorAll()` can also be used to select elements.

Keep in mind that each of these alternatives has its own trade-offs and performance characteristics, and the best approach will depend on the specific use case and requirements.

Related benchmarks:

String head vs legit head (version: 0)

Comparing performance of: String selector vs No selector

Created: 9 years ago by: Registered User

Jump to the latest result

String selector

No selector

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):