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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 Mobile Performance
9/100
These metrics represent real-world Chrome users experience viewing alc.co.jp 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
First Contentful Paint
Largest Contentful Paint
Cumulative Layout Shift
First Input Delay
Metrics
Time to Interactive0/100 27.8 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
Largest Contentful Paint0/100 13.1 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Speed Index1/100 15.8 s
Speed Index shows how quickly the contents of a page are visibly populated. Learn more.
Total Blocking Time4/100 1,670 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Cumulative Layout Shift12/100 0.583
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
First Contentful Paint49/100 4.1 s
First Contentful Paint marks the time at which the first text or image is painted. Learn more.
Should Fix (22)
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 1,002 KiB
6,200 ms
Remove unused JavaScript
Potential savings of 524 KiB
4,760 ms
Efficiently encode images
Potential savings of 585 KiB
4,010 ms
Enable text compression
Potential savings of 319 KiB
2,730 ms
Defer offscreen images
Potential savings of 306 KiB
2,130 ms
Eliminate render-blocking resources
Potential savings of 1,320 ms
1,324 ms
Minify JavaScript
Potential savings of 134 KiB
1,140 ms
Remove unused CSS
Potential savings of 100 KiB
960 ms
Reduce initial server response time
Root document took 650 ms
54 ms
Diagnostics
More information about the performance of your application. These numbers don't directly affect the Performance score.
Does not use passive listeners to improve scrolling performance
Avoid `document.write()`
Reduce the impact of third-party code
Third-party code blocked the main thread for 1,650 ms
Serve static assets with an efficient cache policy
109 resources found
Minimize main-thread work
13.7 s
Reduce JavaScript execution time
7.7 s
Avoid enormous network payloads
Total size was 3,493 KiB
Avoid long main-thread tasks
20 long tasks found
Avoid chaining critical requests
11 chains found
User Timing marks and measures
6 user timings
Largest Contentful Paint element
1 element found
Keep request counts low and transfer sizes small
388 requests • 3,493 KiB
Avoid large layout shifts
5 elements found
Passed Audits (8)
Avoid multiple page redirects
Potential savings of 630 ms
Avoids an excessive DOM size
486 elements
All text remains visible during webfont loads
Preload key requests
Preconnect to required origins
Use video formats for animated content
Properly size images
Potential savings of 5 KiB
Minify CSS
Potential savings of 9 KiB
alc.co.jp Mobile SEO
54/100
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 (6)
Content Best Practices
Format your HTML in a way that enables crawlers to better understand your app’s content.
Document does not have a meta description
Image elements do not have `[alt]` attributes
Crawling and Indexing
To appear in search results, crawlers need access to your app.
Links are not crawlable
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
Document doesn't use legible font sizes
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale`
Passed Audits (7)
Document has a `<title>` element
Document avoids plugins
robots.txt is valid
Page has successful HTTP status code
Document has a valid `hreflang`
Page isn’t blocked from indexing
Links have descriptive text
alc.co.jp Mobile Best Practices
54/100
These checks highlight opportunities to improve the overall code health of alc.co.jp 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 (6)
General
Browser errors were logged to the console
Trust and Safety
Does not use HTTPS
1 insecure request found
Includes front-end JavaScript libraries with known security vulnerabilities
6 vulnerabilities detected
Links to cross-origin destinations are unsafe
User Experience
Serves images with low resolution
Browser Compatibility
Page lacks the HTML doctype, thus triggering quirks-mode
Passed Audits (8)
Avoids Application Cache
Allows users to paste into password fields
Avoids deprecated APIs
Avoids requesting the notification permission on page load
Avoids requesting the geolocation permission on page load
Detected JavaScript libraries
Properly defines charset
Displays images with correct aspect ratio
alc.co.jp Mobile Progressive Web App
18/100
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)
Installable
Does not use HTTPS
1 insecure request found
Web app manifest does not meet the installability requirements
Does not register a service worker that controls page and `start_url`
PWA Optimized
Manifest doesn't have a maskable icon
Is not configured for a custom splash screen
Does not set a theme color for the address bar.
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale`
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 27.8 s
Passed Audits (4)
Provides a valid `apple-touch-icon`
Content is sized correctly for the viewport
Redirects HTTP traffic to HTTPS
Contains some content when JavaScript is not available
alc.co.jp Mobile 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 (5)
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
`<frame>` or `<iframe>` elements do not have a title
Image elements do not have `[alt]` attributes
Form elements do not have associated labels
Contrast
These are opportunities to improve the legibility of your content.
Background and foreground colors do not have a sufficient contrast ratio.
Passed Audits (10)
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
Document has a `<title>` element
The page contains a heading, skip link, or landmark region
Heading elements appear in a sequentially-descending order
`[id]` attributes on active, focusable elements are unique
`<html>` element has a valid value for its `[lang]` attribute
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
`<html>` element has a `[lang]` attribute
`[aria-hidden="true"]` is not present on the document `<body>`
Mobile Usability
99/100
These checks validate how easily a visitor can use alc.co.jp 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
25/100
These checks analyze the performance of alc.co.jp 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 (7)
Optimize images
Leverage browser caching
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Enable compression
Minify JavaScript
Minify HTML
Minify CSS
Passed Audits (3)
Avoid landing page redirects
Reduce server response time
Prioritize visible content
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