Alc.co.jp Site Title

英語学習・TOEIC対策・英辞郎 on the WEB | アルク

Alc.co.jp Meta Description

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 Test Results

Alc.co.jp Mobile Performance: 9/100
Quick overview:
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
Image formats like JPEG 2000, JPEG XR, and WebP often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. Learn more.
Remove unused JavaScript. Potential savings of 524 KiB
Remove unused JavaScript to reduce bytes consumed by network activity. Learn more.
Efficiently encode images. Potential savings of 585 KiB
Optimized images load faster and consume less cellular data. Learn more.
Enable text compression. Potential savings of 319 KiB
Text-based resources should be served with compression (gzip, deflate or brotli) to minimize total network bytes. Learn more.
Defer offscreen images. Potential savings of 306 KiB
Consider lazy-loading offscreen and hidden images after all critical resources have finished loading to lower time to interactive. Learn more.
Eliminate render-blocking resources. Potential savings of 1,320 ms
Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles. Learn more.
Minify JavaScript. Potential savings of 134 KiB
Minifying JavaScript files can reduce payload sizes and script parse time. Learn more.
Remove unused CSS. Potential savings of 100 KiB
Remove dead rules from stylesheets and defer the loading of CSS not used for above-the-fold content to reduce unnecessary bytes consumed by network activity. Learn more.
Reduce initial server response time. Root document took 650 ms
Keep the server response time for the main document short because all other requests depend on it. Learn more.
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
Consider marking your touch and wheel event listeners as `passive` to improve your page's scroll performance. Learn more.
Avoid `document.write()`
For users on slow connections, external scripts dynamically injected via `document.write()` can delay page load by tens of seconds. Learn more.
Reduce the impact of third-party code
Third-party code blocked the main thread for 1,650 ms
Third-party code can significantly impact load performance. Limit the number of redundant third-party providers and try to load third-party code after your page has primarily finished loading. Learn more.
Serve static assets with an efficient cache policy
109 resources found
A long cache lifetime can speed up repeat visits to your page. Learn more.
Minimize main-thread work
13.7 s
Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn more
Reduce JavaScript execution time
7.7 s
Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn more.
Avoid enormous network payloads
Total size was 3,493 KiB
Large network payloads cost users real money and are highly correlated with long load times. Learn more.
Avoid long main-thread tasks
20 long tasks found
Lists the longest tasks on the main thread, useful for identifying worst contributors to input delay. Learn more
Avoid chaining critical requests
11 chains found
The Critical Request Chains below show you what resources are loaded with a high priority. Consider reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load. Learn more.
User Timing marks and measures
6 user timings
Consider instrumenting your app with the User Timing API to measure your app's real-world performance during key user experiences. Learn more.
Largest Contentful Paint element
1 element found
This is the largest contentful element painted within the viewport. Learn More
Keep request counts low and transfer sizes small
388 requests • 3,493 KiB
To set budgets for the quantity and size of page resources, add a budget.json file. Learn more.
Avoid large layout shifts
5 elements found
These DOM elements contribute most to the CLS of the page.

Alc.co.jp Mobile SEO: 54/100
Quick overview:
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
Meta descriptions may be included in search results to concisely summarize page content. Learn more.
Image elements do not have `[alt]` attributes
Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more.
Crawling and Indexing
To appear in search results, crawlers need access to your app.
Links are not crawlable
Search engines may use `href` attributes on links to crawl websites. Ensure that the `href` attribute of anchor elements links to an appropriate destination, so more pages of the site can be discovered. Learn More
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
Interactive elements like buttons and links should be large enough (48x48px), and have enough space around them, to be easy enough to tap without overlapping onto other elements. Learn more. Tap targets are too small because there's no viewport meta tag optimized for mobile screens
Document doesn't use legible font sizes
Font sizes less than 12px are too small to be legible and require mobile visitors to “pinch to zoom” in order to read. Strive to have >60% of page text ≥12px. Learn more. Text is illegible because there's no viewport meta tag optimized for mobile screens.
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale`
Add a `<meta name="viewport">` tag to optimize your app for mobile screens. Learn more. No `<meta name="viewport">` tag found

Alc.co.jp Mobile Best Practices: 54/100
Quick overview:
General
Browser errors were logged to the console
Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more
Trust and Safety
Does not use HTTPS
1 insecure request found
All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being servedover HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more.
Includes front-end JavaScript libraries with known security vulnerabilities
6 vulnerabilities detected
Some third-party scripts may contain known security vulnerabilities that are easily identified and exploited by attackers. Learn more.
Links to cross-origin destinations are unsafe
Add `rel="noopener"` or `rel="noreferrer"` to any external links to improve performance and prevent security vulnerabilities. Learn more.
User Experience
Serves images with low resolution
Image natural dimensions should be proportional to the display size and the pixel ratio to maximize image clarity. Learn more.
Browser Compatibility
Page lacks the HTML doctype, thus triggering quirks-mode
Specifying a doctype prevents the browser from switching to quirks-mode. Learn more. Document must contain a doctype
Alc.co.jp Mobile Progressive Web App: 18/100
Quick overview:
Installable
Does not use HTTPS
1 insecure request found
All sites should be protected with HTTPS, even ones that don't handle sensitive data. This includes avoiding mixed content, where some resources are loaded over HTTP despite the initial request being servedover HTTPS. HTTPS prevents intruders from tampering with or passively listening in on the communications between your app and your users, and is a prerequisite for HTTP/2 and many new web platform APIs. Learn more.
Web app manifest does not meet the installability requirements
Browsers can proactively prompt users to add your app to their homescreen, which can lead to higher engagement. Learn more. Failures: No manifest was fetched.
Does not register a service worker that controls page and `start_url`
The service worker is the technology that enables your app to use many Progressive Web App features, such as offline, add to homescreen, and push notifications. Learn more.
PWA Optimized
Manifest doesn't have a maskable icon
A maskable icon ensures that the image fills the entire shape without being letterboxed when installing the app on a device. Learn more. No manifest was fetched
Is not configured for a custom splash screen
A themed splash screen ensures a high-quality experience when users launch your app from their homescreens. Learn more. Failures: No manifest was fetched.
Does not set a theme color for the address bar.
The browser address bar can be themed to match your site. Learn more. Failures: No manifest was fetched, No `<meta name="theme-color">` tag found.
Does not have a `<meta name="viewport">` tag with `width` or `initial-scale`
Add a `<meta name="viewport">` tag to optimize your app for mobile screens. Learn more. No `<meta name="viewport">` tag found
Fast and reliable
Current page does not respond with a 200 when offline
If you're building a Progressive Web App, consider using a service worker so that your app can work offline. Learn more.
`start_url` does not respond with a 200 when offline
A service worker enables your web app to be reliable in unpredictable network conditions. Learn more. No usable web app manifest found on page.
Page load is not fast enough on mobile networks
Interactive at 27.8 s
A fast page load over a cellular network ensures a good mobile user experience. Learn more. Your page loads too slowly and is not interactive within 10 seconds. Look at the opportunities and diagnostics in the "Performance" section to learn how to improve.
Alc.co.jp Mobile Accessibility: 60/100
Quick overview:
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
Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn more.
`<frame>` or `<iframe>` elements do not have a title
Screen reader users rely on frame titles to describe the contents of frames. Learn more.
Image elements do not have `[alt]` attributes
Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more.
Form elements do not have associated labels
Labels ensure that form controls are announced properly by assistive technologies, like screen readers. Learn more.
Contrast
These are opportunities to improve the legibility of your content.
Background and foreground colors do not have a sufficient contrast ratio.
Low-contrast text is difficult or impossible for many users to read. Learn more.
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