Jb51.net 脚本之家_www.jb51.net
脚本之家是国内专业的网站建设资源、脚本编程学习类网站，提供asp、php、asp.net、javascript、jquery、vbscript、dos批处理、网页制作、网络编程、网站建设等编程资料。
jb51.net Mobile Performance
46/100
These metrics represent real-world Chrome users experience viewing jb51.net on mobile devices. Reports are focused on loading performance and other critical factors that most affect user experience. Follow our guide to track, optimize, and improve the quality of your web pages.
User Loading Experience
Largest Contentful Paint
First Contentful Paint
First Input Delay
Cumulative Layout Shift
Metrics
Largest Contentful Paint11/100 6.3 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Speed Index12/100 9.4 s
Speed Index shows how quickly the contents of a page are visibly populated. Learn more.
Time to Interactive23/100 10.7 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
First Contentful Paint57/100 3.7 s
First Contentful Paint marks the time at which the first text or image is painted. Learn more.
Total Blocking Time99/100 140 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Cumulative Layout Shift100/100 0
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
Should Fix (16)
Opportunities
These suggestions can help your page load faster. They don't directly affect the Performance score.
Defer offscreen images
Potential savings of 1,711 KiB
7,500 ms
Serve images in next-gen formats
Potential savings of 1,320 KiB
6,780 ms
Efficiently encode images
Potential savings of 825 KiB
4,410 ms
Properly size images
Potential savings of 185 KiB
1,230 ms
Reduce initial server response time
Root document took 1,750 ms
1,155 ms
Eliminate render-blocking resources
Potential savings of 780 ms
780 ms
Enable text compression
Potential savings of 40 KiB
300 ms
Remove unused JavaScript
Potential savings of 21 KiB
240 ms
Diagnostics
More information about the performance of your application. These numbers don't directly affect the Performance score.
Avoid `document.write()`
Serve static assets with an efficient cache policy
67 resources found
Avoid an excessive DOM size
1,231 elements
Minimize main-thread work
3.2 s
Avoid long main-thread tasks
6 long tasks found
Keep request counts low and transfer sizes small
134 requests • 2,169 KiB
Largest Contentful Paint element
1 element found
Avoid chaining critical requests
13 chains found
Passed Audits (12)
Avoid multiple page redirects
Minify JavaScript
Preload key requests
Remove unused CSS
Minify CSS
Use video formats for animated content
Minimize third-party usage
Third-party code blocked the main thread for 70 ms
JavaScript execution time
0.5 s
Preconnect to required origins
Uses passive listeners to improve scrolling performance
All text remains visible during webfont loads
Avoids enormous network payloads
Total size was 2,169 KiB
jb51.net Mobile SEO
83/100
These checks ensure that your page is optimized for search engine results ranking. There are additional factors Lighthouse does not check that may affect your search ranking. Learn more. Run these additional validators on your site to check additional SEO best practices.
Should Fix (3)
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.
Tap targets are not sized appropriately
84% appropriately sized tap targets
Crawling and Indexing
To appear in search results, crawlers need access to your app.
Links are not crawlable
Content Best Practices
Format your HTML in a way that enables crawlers to better understand your app’s content.
Image elements do not have `[alt]` attributes
Passed Audits (10)
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
robots.txt is valid
Document avoids plugins
Document uses legible font sizes
100% legible text
Links have descriptive text
Page isn’t blocked from indexing
Document has a meta description
Document has a valid `hreflang`
Document has a `<title>` element
Page has successful HTTP status code
jb51.net Mobile Best Practices
62/100
These checks highlight opportunities to improve the overall code health of jb51.net mobile page. Current recommendations will help to make your page fast and secure, to create a good user experience and to avoid deprecated technologies.
Should Fix (5)
User Experience
Displays images with incorrect aspect ratio
Trust and Safety
Does not use HTTPS
3 insecure requests found
Links to cross-origin destinations are unsafe
Includes front-end JavaScript libraries with known security vulnerabilities
4 vulnerabilities detected
General
Browser errors were logged to the console
Passed Audits (9)
Page has the HTML doctype
Allows users to paste into password fields
Avoids requesting the notification permission on page load
Avoids Application Cache
Avoids deprecated APIs
Properly defines charset
Serves images with appropriate resolution
Avoids requesting the geolocation permission on page load
Detected JavaScript libraries
jb51.net Mobile Progressive Web App
21/100
These checks validate the aspects of a Progressive Web App. Learn more. These checks are required by the baseline PWA Checklist but are not automatically checked by Lighthouse. They do not affect your score but it's important that you verify them manually.
Should Fix (10)
PWA Optimized
Does not set a theme color for the address bar.
Does not provide a valid `apple-touch-icon`
Manifest doesn't have a maskable icon
Is not configured for a custom splash screen
Installable
Does not use HTTPS
3 insecure requests found
Web app manifest does not meet the installability requirements
Does not register a service worker that controls page and `start_url`
Fast and reliable
Current page does not respond with a 200 when offline
`start_url` does not respond with a 200 when offline
Page load is not fast enough on mobile networks
Interactive at 10.7 s
Passed Audits (4)
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Redirects HTTP traffic to HTTPS
Contains some content when JavaScript is not available
Content is sized correctly for the viewport
jb51.net Mobile Accessibility
36/100
These checks highlight opportunities to improve the accessibility of your web app. Only a subset of accessibility issues can be automatically detected so manual testing is also encouraged. These items address areas which an automated testing tool cannot cover. Learn more in our guide on conducting an accessibility review.
Should Fix (7)
Navigation
These are opportunities to improve keyboard navigation in your application.
`[id]` attributes on active, focusable elements are not unique
Best practices
These items highlight common accessibility best practices.
`[user-scalable="no"]` is used in the `<meta name="viewport">` element or the `[maximum-scale]` attribute is less than 5.
Contrast
These are opportunities to improve the legibility of your content.
Background and foreground colors do not have a sufficient contrast ratio.
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.
Links do not have a discernible name
Image elements do not have `[alt]` attributes
Form elements do not have associated labels
Internationalization and localization
These are opportunities to improve the interpretation of your content by users in different locales.
`<html>` element does not have a `[lang]` attribute
Passed Audits (6)
`[aria-hidden="true"]` is not present on the document `<body>`
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
The page contains a heading, skip link, or landmark region
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
Document has a `<title>` element
Heading elements appear in a sequentially-descending order
Mobile Usability
99/100
These checks validate how easily a visitor can use jb51.net on a mobile device. Test results include a list of any mobile usability problems. Mobile usability problems are issues that can affect a user that visits the page on a mobile (small screen) device, including small font sizes (which are hard to read on a small screen).
Should Fix (1)
Size tap targets appropriately
Passed Audits (4)
Avoid plugins
Configure the viewport
Size content to viewport
Use legible font sizes
Mobile Speed
17/100
These checks analyze the performance of jb51.net on mobile devices and return PageSpeed score and information on how to improve the load time. What makes a good Progressive Web App?
Should Fix (6)
Optimize images
Leverage browser caching
Avoid landing page redirects
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Enable compression
Minify JavaScript
Passed Audits (4)
Reduce server response time
Minify CSS
Minify HTML
Prioritize visible content
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