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ck12.org Desktop Performance
45/100
These metrics represent real-world Chrome users experience viewing ck12.org web page. 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
Cumulative Layout Shift
First Input Delay
First Contentful Paint
Metrics
Cumulative Layout Shift5/100 0.812
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
Total Blocking Time32/100 480 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Largest Contentful Paint43/100 2.6 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Speed Index47/100 2.4 s
Speed Index shows how quickly the contents of a page are visibly populated. Learn more.
First Contentful Paint53/100 1.6 s
First Contentful Paint marks the time at which the first text or image is painted. Learn more.
Time to Interactive70/100 3.5 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
Should Fix (15)
Opportunities
These suggestions can help your page load faster. They don't directly affect the Performance score.
Preload key requests
Potential savings of 840 ms
840 ms
Avoid multiple page redirects
Potential savings of 570 ms
570 ms
Remove unused JavaScript
Potential savings of 355 KiB
290 ms
Eliminate render-blocking resources
Potential savings of 270 ms
266 ms
Diagnostics
More information about the performance of your application. These numbers don't directly affect the Performance score.
Avoid `document.write()`
Ensure text remains visible during webfont load
Serve static assets with an efficient cache policy
46 resources found
Minimize main-thread work
2.9 s
Reduce JavaScript execution time
1.7 s
Avoid an excessive DOM size
884 elements
Avoid chaining critical requests
18 chains found
Avoid long main-thread tasks
9 long tasks found
Avoid large layout shifts
4 elements found
Keep request counts low and transfer sizes small
89 requests • 1,491 KiB
Largest Contentful Paint element
1 element found
Passed Audits (14)
Remove unused CSS
Potential savings of 41 KiB
Enable text compression
Minify JavaScript
Minimize third-party usage
Third-party code blocked the main thread for 0 ms
Initial server response time was short
Root document took 20 ms
Preconnect to required origins
Avoids enormous network payloads
Total size was 1,491 KiB
Use video formats for animated content
Uses passive listeners to improve scrolling performance
Serve images in next-gen formats
Minify CSS
Properly size images
Potential savings of 75 KiB
Defer offscreen images
Potential savings of 20 KiB
Efficiently encode images
ck12.org Desktop SEO
67/100
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 (4)
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.
Links do not have descriptive text
1 link found
Document does not have a valid `rel=canonical`
Image elements do not have `[alt]` attributes
Passed Audits (8)
robots.txt is valid
Document has a valid `hreflang`
Document avoids plugins
Page isn’t blocked from indexing
Page has successful HTTP status code
Document has a `<title>` element
Document has a meta description
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
ck12.org Desktop Best Practices
77/100
These checks highlight opportunities to improve the overall code health of ck12.org 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 (3)
Trust and Safety
Does not use HTTPS
1 insecure request found
Links to cross-origin destinations are unsafe
Includes front-end JavaScript libraries with known security vulnerabilities
5 vulnerabilities detected
Passed Audits (11)
Avoids Application Cache
Avoids requesting the notification permission on page load
Avoids requesting the geolocation permission on page load
Serves images with appropriate resolution
Avoids deprecated APIs
Displays images with correct aspect ratio
Detected JavaScript libraries
No browser errors logged to the console
Allows users to paste into password fields
Page has the HTML doctype
Properly defines charset
ck12.org Desktop Progressive Web App
22/100
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 (9)
Installable
Does not use HTTPS
1 insecure request found
Does not register a service worker that controls page and `start_url`
Web app manifest does not meet the installability requirements
PWA Optimized
Is not configured for a custom splash screen
Does not set a theme color for the address bar.
Manifest doesn't have a maskable icon
Fast and reliable
Page load is not fast enough on mobile networks
Interactive on simulated mobile network at 15.4 s
`start_url` does not respond with a 200 when offline
Current page does not respond with a 200 when offline
Passed Audits (4)
Redirects HTTP traffic to HTTPS
Contains some content when JavaScript is not available
Provides a valid `apple-touch-icon`
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
ck12.org Desktop Accessibility
76/100
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 (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
Form elements do not have associated labels
Image elements do not have `[alt]` attributes
Buttons do not have an accessible name
Passed Audits (18)
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
`[aria-hidden="true"]` elements do not contain focusable descendents
`[aria-*]` attributes match their roles
`[aria-*]` attributes are valid and not misspelled
`[role]` values are valid
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
The page contains a heading, skip link, or landmark region
`[id]` attributes on active, focusable elements are unique
`[role]`s are contained by their required parent element
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
Heading elements appear in a sequentially-descending order
`[aria-*]` attributes have valid values
`<html>` element has a `[lang]` attribute
`<html>` element has a valid value for its `[lang]` attribute
Document has a `<title>` element
`[role]`s have all required `[aria-*]` attributes
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
`[aria-hidden="true"]` is not present on the document `<body>`
Desktop Speed
74/100
These checks analyze the performance of ck12.org on desktop devices and return PageSpeed score and information on how to improve the load time. What makes a good Progressive Web App?
Should Fix (9)
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Avoid landing page redirects
Leverage browser caching
Prioritize visible content
Minify HTML
Minify CSS
Minify JavaScript
Optimize images
Enable compression
Passed Audits (1)
Reduce server response time
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