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name

value

score

weighting

FCP (First Contentful Paint)

Value2.4 s

71/100

10%

LCP (Largest Contentful Paint)

Value4.6 s

35/100

25%

SI (Speed Index)

Value7.2 s

30/100

10%

TBT (Total Blocking Time)

Value10 ms

100/100

30%

CLS (Cumulative Layout Shift)

Value0

100/100

15%

TTI (Time to Interactive)

Value3.5 s

92/100

10%

main

1431 ms

basic.css

682 ms

layout.css

9289 ms

libs.css

1024 ms

jQuery_latest.min.js

2008 ms

Our browser made a total of 88 requests to load all elements on the main page. We found that 68% of them (60 requests) were addressed to the original Class.cn, 18% (16 requests) were made to V2.data.class.cn and 3% (3 requests) were made to Stat.eol.cn. The less responsive or slowest element that took the longest time to load (19.8 sec) belongs to the original domain Class.cn.

Content Size

1.1 MB

After Optimization

451.2 kB

In fact, the total size of Class.cn main page is 1.1 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. 30% of websites need less resources to load. Images take 499.9 kB which makes up the majority of the site volume.

HTML Optimization

-83%

Potential reduce by 55.0 kB

Original 66.4 kB
After minification 61.4 kB
After compression 11.4 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. HTML code on this page is well minified. It is highly recommended that content of this web page should be compressed using GZIP, as it can save up to 55.0 kB or 83% of the original size.

Image Optimization

-38%

Potential reduce by 189.1 kB

Original 499.9 kB
After minification 310.8 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, Class needs image optimization as it can save up to 189.1 kB or 38% of the original volume. The most popular and efficient tools for JPEG and PNG image optimization are Jpegoptim and PNG Crush.

JavaScript Optimization

-75%

Potential reduce by 280.6 kB

Original 372.7 kB
After minification 290.1 kB
After compression 92.1 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 280.6 kB or 75% of the original size.

CSS Optimization

-81%

Potential reduce by 157.9 kB

Original 194.9 kB
After minification 177.2 kB
After compression 36.9 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. Class.cn needs all CSS files to be minified and compressed as it can save up to 157.9 kB or 81% of the original size.

Requests Now

After Optimization

The browser has sent 84 CSS, Javascripts, AJAX and image requests in order to completely render the main page of Class. We recommend that multiple CSS and JavaScript files should be merged into one by each type, as it can help reduce assets requests from 14 to 1 for JavaScripts and from 5 to 1 for CSS and as a result speed up the page load time.

Accessibility Issues

These are opportunities to improve the legibility of your content.

High

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

These are opportunities to improve the interpretation of your content by users in different locales.

High

<html> element does not have a [lang] attribute

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.

High

Image elements do not have [alt] attributes

High

Links do not have a discernible name

Areas of Improvement

High

Does not use HTTPS

High

Includes front-end JavaScript libraries with known security vulnerabilities

Low

Ensure CSP is effective against XSS attacks

High

Displays images with incorrect aspect ratio

High

Serves images with low resolution

Low

Detected JavaScript libraries

Search Engine Optimization Advices

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

High

robots.txt is not valid

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

High

Image elements do not have [alt] attributes

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/).

High

Document uses legible font sizes

Language and Encoding

Language Detected

ZH
Language Claimed

EN
Encoding

UTF-8

Language claimed in HTML meta tag should match the language actually used on the web page. Otherwise Class.cn can be misinterpreted by Google and other search engines. Our service has detected that Chinese is used on the page, and it does not match the claimed English language. Our system also found out that Class.cn 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

class.cn

Open Graph description is not detected on the main page of Class. 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:

Report Summary

Performance

Accessibility

Best Practices

SEO

在线学习网络课程 | 好课网 - 中国教育在线

Page Load Speed

First Response

Resources Loaded

Page Rendered

About Website

Key Findings

Performance Metrics

Measured Metrics

FCP (First Contentful Paint)

LCP (Largest Contentful Paint)

SI (Speed Index)

TBT (Total Blocking Time)

CLS (Cumulative Layout Shift)

TTI (Time to Interactive)

Network Requests Diagram

main

basic.css

layout.css

libs.css

jQuery_latest.min.js

Page Optimization Overview & Recommendations

Content Size

After Optimization

HTML Optimization

Image Optimization

JavaScript Optimization

CSS Optimization

Requests Breakdown

Requests Now

After Optimization

Network Requests Diagram

main

basic.css

layout.css

libs.css

jQuery_latest.min.js

jquery.raty.js

jquery.dragsort.js

lhgcore.lhgdialog.min.js

effect.js

login.js

public.js

libs.js

focus_img.js

stat.php

110051.js

default.css

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