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英語・子供英語・日本語の通信講座や学習書、オンラインサービスを提供するアルクのウェブサイト。あなたのレベルや目的に合った語学学習教材がきっと見つかります。英辞郎 on the WEBやTOEICなどの無料コンテンツも充実。
alc.co.jp Desktop Performance
44/100
These metrics represent real-world Chrome users experience viewing alc.co.jp 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
First Input Delay
First Contentful Paint
Cumulative Layout Shift
Largest Contentful Paint
Metrics
Speed Index8/100 4.2 s
Speed Index shows how quickly the contents of a page are visibly populated. Learn more.
Largest Contentful Paint12/100 4.5 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Time to Interactive19/100 6.8 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
First Contentful Paint48/100 1.6 s
First Contentful Paint marks the time at which the first text or image is painted. Learn more.
Cumulative Layout Shift98/100 0.061
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
Total Blocking Time100/100 20 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Should Fix (20)
Opportunities
These suggestions can help your page load faster. They don't directly affect the Performance score.
Serve images in next-gen formats
Potential savings of 1,392 KiB
1,460 ms
Remove unused JavaScript
Potential savings of 835 KiB
720 ms
Eliminate render-blocking resources
Potential savings of 670 ms
668 ms
Efficiently encode images
Potential savings of 604 KiB
620 ms
Enable text compression
Potential savings of 470 KiB
410 ms
Defer offscreen images
Potential savings of 417 KiB
400 ms
Remove unused CSS
Potential savings of 418 KiB
360 ms
Reduce initial server response time
Root document took 760 ms
165 ms
Properly size images
Potential savings of 149 KiB
140 ms
Diagnostics
More information about the performance of your application. These numbers don't directly affect the Performance score.
Serve static assets with an efficient cache policy
112 resources found
Avoid `document.write()`
Avoid enormous network payloads
Total size was 4,521 KiB
Minimize main-thread work
3.6 s
Reduce JavaScript execution time
1.5 s
Avoid long main-thread tasks
6 long tasks found
Keep request counts low and transfer sizes small
363 requests • 4,521 KiB
Avoid large layout shifts
5 elements found
Largest Contentful Paint element
1 element found
Avoid chaining critical requests
27 chains found
User Timing marks and measures
6 user timings
Passed Audits (10)
Avoids an excessive DOM size
648 elements
All text remains visible during webfont loads
Preload key requests
Minify JavaScript
Potential savings of 3 KiB
Preconnect to required origins
Minify CSS
Potential savings of 81 KiB
Minimize third-party usage
Third-party code blocked the main thread for 20 ms
Use video formats for animated content
Avoid multiple page redirects
Potential savings of 190 ms
Uses passive listeners to improve scrolling performance
alc.co.jp Desktop SEO
91/100
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 (1)
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)
Document has a `<title>` element
robots.txt is valid
Document has a meta description
Document has a valid `hreflang`
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Links have descriptive text
Document avoids plugins
Links are crawlable
Page has successful HTTP status code
Page isn’t blocked from indexing
alc.co.jp Desktop Best Practices
62/100
These checks highlight opportunities to improve the overall code health of alc.co.jp 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)
General
Browser errors were logged to the console
Trust and Safety
Includes front-end JavaScript libraries with known security vulnerabilities
6 vulnerabilities detected
Links to cross-origin destinations are unsafe
Does not use HTTPS
1 insecure request found
Browser Compatibility
Page lacks the HTML doctype, thus triggering quirks-mode
Passed Audits (9)
Avoids requesting the notification permission on page load
Avoids requesting the geolocation permission on page load
Avoids deprecated APIs
Avoids Application Cache
Displays images with correct aspect ratio
Properly defines charset
Serves images with appropriate resolution
Allows users to paste into password fields
Detected JavaScript libraries
alc.co.jp Desktop Progressive Web App
19/100
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.
Manifest doesn't have a maskable icon
Is not configured for a custom splash screen
Does not provide a valid `apple-touch-icon`
Installable
Web app manifest does not meet the installability requirements
Does not register a service worker that controls page and `start_url`
Does not use HTTPS
1 insecure request found
Fast and reliable
Page load is not fast enough on mobile networks
Interactive on simulated mobile network at 31.2 s
`start_url` does not respond with a 200 when offline
Current page does not respond with a 200 when offline
Passed Audits (3)
Contains some content when JavaScript is not available
Redirects HTTP traffic to HTTPS
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
alc.co.jp Desktop Accessibility
60/100
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 (6)
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.
Image elements do not have `[alt]` attributes
`<frame>` or `<iframe>` elements do not have a title
Links do not have a discernible name
Form elements do not have associated labels
Tables and lists
These are opportunities to to improve the experience of reading tabular or list data using assistive technology, like a screen reader.
Lists do not contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
Contrast
These are opportunities to improve the legibility of your content.
Background and foreground colors do not have a sufficient contrast ratio.
Passed Audits (12)
Document has a `<title>` element
Heading elements appear in a sequentially-descending order
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
Definition list items are wrapped in `<dl>` elements
`[accesskey]` values are unique
`<html>` element has a `[lang]` attribute
`[aria-hidden="true"]` is not present on the document `<body>`
`<html>` element has a valid value for its `[lang]` attribute
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
`[id]` attributes on active, focusable elements are unique
The page contains a heading, skip link, or landmark region
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
Desktop Speed
24/100
These checks analyze the performance of alc.co.jp 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 (7)
Optimize images
Enable compression
Leverage browser caching
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Minify CSS
Minify HTML
Minify JavaScript
Passed Audits (3)
Avoid landing page redirects
Reduce server response time
Prioritize visible content
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