Acs.org American Chemical Society
acs.org Mobile Performance
11/100
These metrics represent real-world Chrome users experience viewing acs.org 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
Cumulative Layout Shift
Largest Contentful Paint
First Input Delay
First Contentful Paint
Metrics
Largest Contentful Paint0/100 14.0 s
Largest Contentful Paint marks the time at which the largest text or image is painted. Learn More
Total Blocking Time1/100 2,110 ms
Sum of all time periods between FCP and Time to Interactive, when task length exceeded 50ms, expressed in milliseconds. Learn more.
Time to Interactive3/100 18.7 s
Time to interactive is the amount of time it takes for the page to become fully interactive. Learn more.
Cumulative Layout Shift6/100 0.773
Cumulative Layout Shift measures the movement of visible elements within the viewport. Learn more.
Speed Index8/100 10.3 s
Speed Index shows how quickly the contents of a page are visibly populated. 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.
Should Fix (21)
Opportunities
These suggestions can help your page load faster. They don't directly affect the Performance score.
Avoid multiple page redirects
Potential savings of 21,900 ms
21,900 ms
Defer offscreen images
Potential savings of 417 KiB
2,830 ms
Remove unused JavaScript
Potential savings of 383 KiB
2,550 ms
Serve images in next-gen formats
Potential savings of 178 KiB
1,650 ms
Eliminate render-blocking resources
Potential savings of 1,640 ms
1,636 ms
Minify JavaScript
Potential savings of 145 KiB
1,050 ms
Remove unused CSS
Potential savings of 80 KiB
450 ms
Efficiently encode images
Potential savings of 21 KiB
300 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
Reduce the impact of third-party code
Third-party code blocked the main thread for 1,000 ms
Ensure text remains visible during webfont load
Avoid `document.write()`
Serve static assets with an efficient cache policy
56 resources found
Minimize main-thread work
8.7 s
Reduce JavaScript execution time
5.5 s
Avoid an excessive DOM size
1,032 elements
Keep request counts low and transfer sizes small
148 requests • 2,111 KiB
Avoid long main-thread tasks
20 long tasks found
Largest Contentful Paint element
1 element found
Avoid chaining critical requests
15 chains found
Avoid large layout shifts
5 elements found
Passed Audits (8)
Initial server response time was short
Root document took 190 ms
Use video formats for animated content
Properly size images
Enable text compression
Preload key requests
Avoids enormous network payloads
Total size was 2,111 KiB
Minify CSS
Preconnect to required origins
acs.org Mobile SEO
72/100
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)
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
Links do not have descriptive text
1 link found
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
42% appropriately sized tap targets
Crawling and Indexing
To appear in search results, crawlers need access to your app.
Links are not crawlable
Passed Audits (9)
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Page has successful HTTP status code
Document has a `<title>` element
Document has a meta description
Document avoids plugins
Document has a valid `hreflang`
robots.txt is valid
Page isn’t blocked from indexing
Document uses legible font sizes
100% legible text
acs.org Mobile Best Practices
69/100
These checks highlight opportunities to improve the overall code health of acs.org 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 (4)
Trust and Safety
Includes front-end JavaScript libraries with known security vulnerabilities
6 vulnerabilities detected
Does not use HTTPS
1 insecure request found
General
Uses deprecated APIs
1 warning found
User Experience
Serves images with low resolution
Passed Audits (10)
Properly defines charset
Detected JavaScript libraries
Avoids Application Cache
Avoids requesting the geolocation permission on page load
Links to cross-origin destinations are safe
Page has the HTML doctype
No browser errors logged to the console
Allows users to paste into password fields
Avoids requesting the notification permission on page load
Displays images with correct aspect ratio
acs.org 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.
Manifest doesn't have a maskable icon
Is not configured for a custom splash screen
Does not provide a valid `apple-touch-icon`
Fast and reliable
Current page does not respond with a 200 when offline
Page load is not fast enough on mobile networks
Interactive at 18.7 s
`start_url` does not respond with a 200 when offline
Installable
Does not register a service worker that controls page and `start_url`
Web app manifest does not meet the installability requirements
Does not use HTTPS
1 insecure request found
Passed Audits (4)
Has a `<meta name="viewport">` tag with `width` or `initial-scale`
Contains some content when JavaScript is not available
Redirects HTTP traffic to HTTPS
Content is sized correctly for the viewport
acs.org Mobile Accessibility
66/100
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 (8)
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
Links do not have a discernible name
Form elements do not have associated labels
Buttons do not have an accessible name
ARIA
These are opportunities to improve the usage of ARIA in your application which may enhance the experience for users of assistive technology, like a screen reader.
`[aria-*]` attributes do not have valid values
ARIA IDs are not unique
Navigation
These are opportunities to improve keyboard navigation in your application.
Heading elements are not in a sequentially-descending order
Contrast
These are opportunities to improve the legibility of your content.
Background and foreground colors do not have a sufficient contrast ratio.
Passed Audits (19)
`[aria-*]` attributes are valid and not misspelled
`[id]` attributes on active, focusable elements are unique
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
`[aria-*]` attributes match their roles
`[role]` values are valid
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
No element has a `[tabindex]` value greater than 0
`[aria-hidden="true"]` is not present on the document `<body>`
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
The page contains a heading, skip link, or landmark region
Definition list items are wrapped in `<dl>` elements
`[aria-hidden="true"]` elements do not contain focusable descendents
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Document has a `<title>` element
`<html>` element has a valid value for its `[lang]` attribute
`[role]`s have all required `[aria-*]` attributes
`<html>` element has a `[lang]` attribute
List items (`<li>`) are contained within `<ul>` or `<ol>` parent elements
`[role]`s are contained by their required parent element
Mobile Usability
99/100
These checks validate how easily a visitor can use acs.org 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
52/100
These checks analyze the performance of acs.org 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 (8)
Eliminate render-blocking JavaScript and CSS in above-the-fold content
Leverage browser caching
Avoid landing page redirects
Prioritize visible content
Optimize images
Enable compression
Minify HTML
Minify JavaScript
Passed Audits (2)
Reduce server response time
Minify CSS
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