User Experience Performance Single Region Diagnostic Results

Webpage: https://www.jeol.com

Device: Desktop Computer

Region: United States East (Virginia)

Single Region Score

53
Page Performance Needs Improvement
A total of 25 improvements can achieve a higher score
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 how to make links accessible].

List items (`<li>`) are not contained within `<ul>`, `<ol>` or `<menu>` parent elements.

Screen readers require list items (`

  • `) to be contained within a parent `
    • Largest Contentful Paint element

    This is the largest contentful element painted within the viewport. [Learn more about the Largest Contentful Paint element]

    Avoid an excessive DOM size

    A large DOM will increase memory usage, cause longer [style calculations], and produce costly [layout reflows]. [Learn how to avoid an excessive DOM size].

    Avoid large layout shifts

    These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to [windowing]. [Learn how to improve CLS]

    Image elements have `[alt]` attributes that are redundant text.

    Informative elements should aim for short, descriptive alternative text. Alternative text that is exactly the same as the text adjacent to the link or image is potentially confusing for screen reader users, because the text will be read twice. [Learn more about the `alt` attribute].

    Third parties

    Third party code can significantly impact load performance. [Reduce and defer loading of third party code] to prioritize your page's content.

    Reduce unused CSS

    Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. [Learn how to reduce unused CSS].

    `[aria-hidden="true"]` elements contain focusable descendents

    Focusable descendents within an `[aria-hidden="true"]` element prevent those interactive elements from being available to users of assistive technologies like screen readers. [Learn how `aria-hidden` affects focusable elements].

    Reduce unused JavaScript

    Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. [Learn how to reduce unused JavaScript].

    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 how to make links crawlable]

    Background and foreground colors do not have a sufficient contrast ratio.

    Low-contrast text is difficult or impossible for many users to read. [Learn how to provide sufficient color contrast].

    Eliminate render-blocking resources

    Resources are blocking the first paint of your page. Consider delivering critical JS/CSS inline and deferring all non-critical JS/styles. [Learn how to eliminate render-blocking resources].

    Serve images in next-gen formats

    Image formats like WebP and AVIF often provide better compression than PNG or JPEG, which means faster downloads and less data consumption. [Learn more about modern image formats].

    Minify JavaScript

    Minifying JavaScript files can reduce payload sizes and script parse time. [Learn how to minify JavaScript].

    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 about this errors in console diagnostic audit]

    Efficiently encode images

    Optimized images load faster and consume less cellular data. [Learn how to efficiently encode images].

    Layout shift culprits

    Layout shifts occur when elements move absent any user interaction. [Investigate the causes of layout shifts], such as elements being added, removed, or their fonts changing as the page loads.

    Properly size images

    Serve images that are appropriately-sized to save cellular data and improve load time. [Learn how to size images].

    Links do not have descriptive text

    Descriptive link text helps search engines understand your content. [Learn how to make links more accessible].

    Elements with visible text labels do not have matching accessible names.

    Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. [Learn more about accessible names].

    Lists do not contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).

    Screen readers have a specific way of announcing lists. Ensuring proper list structure aids screen reader output. [Learn more about proper list structure].

    Minimize main-thread work

    Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. [Learn how to minimize main-thread work]

    Minify CSS

    Minifying CSS files can reduce network payload sizes. [Learn how to minify CSS].

    LCP request discovery

    Optimize LCP by making the LCP image [discoverable] from the HTML immediately, and [avoiding lazy-loading]

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