Tools & Wizards About Us

Report Summary

  • 52

    Performance

    Renders faster than
    69% of other websites

  • 79

    Accessibility

    Visual factors better than
    that of 47% of websites

  • 83

    Best Practices

    More advanced features
    available than in
    55% of websites

  • 80

    SEO

    Google-friendlier than
    42% of websites

learn-js.org

Learn JavaScript - Free Interactive JavaScript Tutorial

Page Load Speed

1.2 sec in total

First Response

47 ms

Resources Loaded

674 ms

Page Rendered

509 ms

About Website

Visit learn-js.org now to see the best up-to-date Learn Js content for United States and also check out these interesting facts you probably never knew about learn-js.org

learn-js.org is a free interactive JavaScript tutorial for people who want to learn JavaScript, fast.

Visit learn-js.org

Key Findings

We analyzed Learn-js.org page load time and found that the first response time was 47 ms and then it took 1.2 sec to load all DOM resources and completely render a web page. This is quite a good result, as only 25% of websites can load faster.

Performance Metrics

learn-js.org performance score

52

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value1.6 s

94/100

10%

LCP (Largest Contentful Paint)

Value2.2 s

95/100

25%

SI (Speed Index)

Value7.2 s

30/100

10%

TBT (Total Blocking Time)

Value5,070 ms

0/100

30%

CLS (Cumulative Layout Shift)

Value0.018

100/100

15%

TTI (Time to Interactive)

Value13.8 s

10/100

10%

Network Requests Diagram

learn-js.org

47 ms

learn-js.org

87 ms

bootstrap.min.css

76 ms

codemirror.css

70 ms

xq-light-media.css

66 ms

Our browser made a total of 45 requests to load all elements on the main page. We found that 69% of them (31 requests) were addressed to the original Learn-js.org, 9% (4 requests) were made to Cdnjs.cloudflare.com and 4% (2 requests) were made to Pagead2.googlesyndication.com. The less responsive or slowest element that took the longest time to load (297 ms) relates to the external source Pagead2.googlesyndication.com.

Page Optimization Overview & Recommendations

Page size can be reduced by 746.3 kB (23%)

Content Size

3.2 MB

After Optimization

2.5 MB

  • HTML
  • Images
  • JavaScript

In fact, the total size of Learn-js.org main page is 3.2 MB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 45% of websites need less resources to load. Images take 2.6 MB which makes up the majority of the site volume.

HTML Optimization

-80%

Potential reduce by 27.9 kB

  • Original 34.8 kB
  • After minification 28.1 kB
  • After compression 6.9 kB

HTML content can be minified and compressed by a website’s server. The most efficient way is to compress content using GZIP which reduces data amount travelling through the network between server and browser. This page needs HTML code to be minified as it can gain 6.7 kB, which is 19% of the original size. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 27.9 kB or 80% of the original size.

Image Optimization

-15%

Potential reduce by 390.0 kB

  • Original 2.6 MB
  • After minification 2.2 MB

Image size optimization can help to speed up a website loading time. The chart above shows the difference between the size before and after optimization. Obviously, Learn Js needs image optimization as it can save up to 390.0 kB or 15% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization

-56%

Potential reduce by 328.5 kB

  • Original 590.9 kB
  • After minification 590.9 kB
  • After compression 262.5 kB

It’s better to minify JavaScript in order to improve website performance. The diagram shows the current total size of all JavaScript files against the prospective JavaScript size after its minification and compression. It is highly recommended that all JavaScript files should be compressed and minified as it can save up to 328.5 kB or 56% of the original size.

Requests Breakdown

Number of requests can be reduced by 25 (61%)

Requests Now

41

After Optimization

16

  • AJAX
  • Images
  • JavaScript
  • CSS

The browser has sent 41 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Learn Js. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 19 to 1 for JavaScripts and from 8 to 1 for CSS and as a result speed up the page load time.

Network Requests Diagram

Accessibility Review

learn-js.org accessibility score

79

Accessibility Issues

Names and labels

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Impact

Issue

High

Buttons do not have an accessible name

High

Image elements do not have [alt] attributes

High

Links do not have a discernible name

Contrast

These are opportunities to improve the legibility of your content.

Impact

Issue

High

Background and foreground colors do not have a sufficient contrast ratio.

Navigation

These are opportunities to improve keyboard navigation in your application.

Impact

Issue

High

Heading elements are not in a sequentially-descending order

Best Practices

learn-js.org best practices score

83

Areas of Improvement

Trust and Safety

Impact

Issue

High

Does not use HTTPS

High

Includes front-end JavaScript libraries with known security vulnerabilities

Low

Ensure CSP is effective against XSS attacks

General

Impact

Issue

Low

Detected JavaScript libraries

High

Page has valid source maps

SEO Factors

learn-js.org SEO score

80

Search Engine Optimization Advices

Content Best Practices

Format your HTML in a way that enables crawlers to better understand your app’s content.

Impact

Issue

High

Links do not have descriptive text

High

Image elements do not have [alt] attributes

Mobile Friendly

Make sure your pages are mobile friendly so users don’t have to pinch or zoom in order to read the content pages. [Learn more](https://developers.google.com/search/mobile-sites/).

Impact

Issue

High

Document uses legible font sizes

High

Tap targets are not sized appropriately

Language and Encoding

  • Language Detected

    EN

  • Language Claimed

    EN

  • Encoding

    UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Learn-js.org can be misinterpreted by Google and other search engines. Our service has detected that English is used on the page, and it matches the claimed language. Our system also found out that Learn-js.org main page’s claimed encoding is utf-8. Use of this encoding format is the best practice as the main page visitors from all over the world won’t have any issues with symbol transcription.

Social Sharing Optimization

Open Graph description is not detected on the main page of Learn Js. Lack of Open Graph description can be counter-productive for their social media presence, as such a description allows converting a website homepage (or other pages) into good-looking, rich and well-structured posts, when it is being shared on Facebook and other social media. For example, adding the following code snippet into HTML <head> tag will help to represent this web page correctly in social networks: