User Experience Performance Single Region Diagnostic Results

Webpage: https://www.yahon.com.vn

Device: Desktop Computer

Region: United States West (Oregon)

Single Region Score

39
Poor Page Performance
A total of 23 improvements can achieve a better score
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].

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.

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].

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].

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]

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].

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].

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].

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 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]

Defer offscreen images

Consider lazy-loading offscreen and hidden images after all critical resources have finished loading to lower time to interactive. [Learn how to defer offscreen images].

Largest Contentful Paint element

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

Properly size images

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

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].

Efficiently encode images

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

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 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].

    `<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].

    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].

    `<html>` element does not have a `[lang]` attribute

    If a page doesn't specify a `lang` attribute, a screen reader assumes that the page is in the default language that the user chose when setting up the screen reader. If the page isn't actually in the default language, then the screen reader might not announce the page's text correctly. [Learn more about the `lang` attribute].

    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].

    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].

    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]

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