Report Summary

  • 17

    Performance

    Renders faster than
    32% of other websites

  • 97

    Accessibility

    Visual factors better than
    that of 92% of websites

  • 83

    Best Practices

    More advanced features
    available than in
    56% of websites

  • 77

    SEO

    Google-friendlier than
    36% of websites

Page Load Speed

5 sec in total

First Response

966 ms

Resources Loaded

3.9 sec

Page Rendered

125 ms

student.onlinejazyky.cz screenshot

About Website

Welcome to student.onlinejazyky.cz homepage info - get ready to check Student Online Jazyky best content for Czech Republic right away, or after learning these important things about student.onlinejazyky.cz

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Key Findings

We analyzed Student.onlinejazyky.cz page load time and found that the first response time was 966 ms and then it took 4.1 sec to load all DOM resources and completely render a web page. This is a poor result, as 65% of websites can load faster.

Performance Metrics

student.onlinejazyky.cz performance score

17

Measured Metrics

name

value

score

weighting

FCP (First Contentful Paint)

Value6.4 s

2/100

10%

LCP (Largest Contentful Paint)

Value16.0 s

0/100

25%

SI (Speed Index)

Value9.1 s

13/100

10%

TBT (Total Blocking Time)

Value2,240 ms

6/100

30%

CLS (Cumulative Layout Shift)

Value0.104

88/100

15%

TTI (Time to Interactive)

Value16.2 s

6/100

10%

Network Requests Diagram

student.onlinejazyky.cz

966 ms

users-login.html

867 ms

bootstrap.min.css

126 ms

webfont.css

246 ms

elusive-webfont.css

342 ms

Our browser made a total of 63 requests to load all elements on the main page. We found that 2% of them (1 request) were addressed to the original Student.onlinejazyky.cz, 59% (37 requests) were made to Onlinejazyky.cz and 17% (11 requests) were made to Shared.optimato.cz. The less responsive or slowest element that took the longest time to load (966 ms) belongs to the original domain Student.onlinejazyky.cz.

Page Optimization Overview & Recommendations

Page size can be reduced by 564.4 kB (65%)

Content Size

869.6 kB

After Optimization

305.2 kB

In fact, the total size of Student.onlinejazyky.cz main page is 869.6 kB. This result falls beyond the top 1M of websites and identifies a large and not optimized web page that may take ages to load. 40% of websites need less resources to load. Javascripts take 506.9 kB which makes up the majority of the site volume.

HTML Optimization

-73%

Potential reduce by 13.3 kB

  • Original 18.2 kB
  • After minification 15.9 kB
  • After compression 4.9 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 2.4 kB, which is 13% 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 13.3 kB or 73% of the original size.

Image Optimization

-35%

Potential reduce by 31.0 kB

  • Original 89.3 kB
  • After minification 58.3 kB

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, Student Online Jazyky needs image optimization as it can save up to 31.0 kB or 35% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization

-61%

Potential reduce by 308.7 kB

  • Original 506.9 kB
  • After minification 480.7 kB
  • After compression 198.2 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 308.7 kB or 61% of the original size.

CSS Optimization

-83%

Potential reduce by 211.4 kB

  • Original 255.2 kB
  • After minification 220.7 kB
  • After compression 43.8 kB

CSS files minification is very important to reduce a web page rendering time. The faster CSS files can load, the earlier a page can be rendered. Student.onlinejazyky.cz needs all CSS files to be minified and compressed as it can save up to 211.4 kB or 83% of the original size.

Requests Breakdown

Number of requests can be reduced by 44 (75%)

Requests Now

59

After Optimization

15

The browser has sent 59 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Student Online Jazyky. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 27 to 1 for JavaScripts and from 19 to 1 for CSS and as a result speed up the page load time.

Accessibility Review

student.onlinejazyky.cz accessibility score

97

Accessibility Issues

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.

Best Practices

student.onlinejazyky.cz 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

Missing source maps for large first-party JavaScript

SEO Factors

student.onlinejazyky.cz SEO score

77

Search Engine Optimization Advices

Crawling and Indexing

To appear in search results, crawlers need access to your app.

Impact

Issue

High

Links are not crawlable

High

robots.txt is not valid

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

Language and Encoding

  • Language Detected

    N/A

  • Language Claimed

    N/A

  • Encoding

    WINDOWS-1250

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Student.onlinejazyky.cz can be misinterpreted by Google and other search engines. Unfortunately we cannot identify language used on the page (probably there is a mix of languages, too little text or something else) and no language is claimed in <html> or <meta> tags either. Our system also found out that Student.onlinejazyky.cz main page’s claimed encoding is windows-1250. Changing it to UTF-8 can be a good choice, as this format is commonly used for encoding all over the web and thus their visitors won’t have any troubles with symbol transcription or reading.

Social Sharing Optimization

Open Graph description is not detected on the main page of Student Online Jazyky. 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: