User Experience Performance Single Region Diagnostic Results

Webpage: https://cosmos.com.vn

Device: Desktop Computer

Region: Ireland (Dublin)

Single Region Score

60
Page Performance Needs Improvement
A total of 33 improvements can achieve a higher score
List items (`<li>`) are not contained within `<ul>`, `<ol>` or `<menu>` parent elements.

Screen readers require list items (`

  • `) to be contained within a parent `
  • Reduce JavaScript execution time

    Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. [Learn how to reduce Javascript execution time].

    Minify JavaScript

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

    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.

    Document does not have a meta description

    Meta descriptions may be included in search results to concisely summarize page content. [Learn more about the meta description].

    Minify CSS

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

    Does not use HTTPS

    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 served over 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 about HTTPS].

    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]

    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].

    Issues were logged in the `Issues` panel in Chrome Devtools

    Issues logged to the `Issues` panel in Chrome Devtools indicate unresolved problems. They can come from network request failures, insufficient security controls, and other browser concerns. Open up the Issues panel in Chrome DevTools for more details on each issue.

    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]

    Render blocking requests

    Requests are blocking the page's initial render, which may delay LCP. [Deferring or inlining] can move these network requests out of the critical path.

    Third parties

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

    Avoid serving legacy JavaScript to modern browsers

    Polyfills and transforms enable legacy browsers to use new JavaScript features. However, many aren't necessary for modern browsers. For your bundled JavaScript, adopt a modern script deployment strategy using [module/nomodule feature detection] to reduce the amount of code shipped to modern browsers, while retaining support for legacy browsers. [Learn how to serve modern JavaScript]

    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 about the `alt` attribute].

    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].

    LCP request discovery

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

    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]

    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].

    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].

    Heading elements are not in a sequentially-descending order

    Properly ordered headings that do not skip levels convey the semantic structure of the page, making it easier to navigate and understand when using assistive technologies. [Learn more about heading order].

    Efficiently encode images

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

    Avoid multiple page redirects

    Redirects introduce additional delays before the page can be loaded. [Learn how to avoid page redirects].

    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].

    Largest Contentful Paint element

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

    Improve image delivery

    Reducing the download time of images can improve the perceived load time of the page and LCP. [Learn more about optimizing image size]

    `<frame>` or `<iframe>` elements do not have a title

    Screen reader users rely on frame titles to describe the contents of frames. [Learn more about frame titles].

    Some third-party resources can be lazy loaded with a facade

    Some third-party embeds can be lazy loaded. Consider replacing them with a facade until they are required. [Learn how to defer third-parties with a facade].

    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].

    Reduce the impact of third-party code

    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 how to minimize third-party impact].

    Uses third-party cookies

    Chrome is moving towards a new experience that allows users to choose to browse without third-party cookies. [Learn more about third-party cookies].

    Document request latency

    Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

    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].

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