User Experience Performance Single Region Diagnostic Results

Webpage: https://www.invisalign.com.hk

Device: Desktop Computer

Region: Germany (Frankfurt)

Single Region Score

57
Page Performance Needs Improvement
A total of 18 improvements can achieve a higher score
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].

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.

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]

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].

robots.txt is not valid

If your robots.txt file is malformed, crawlers may not be able to understand how you want your website to be crawled or indexed. [Learn more about robots.txt].

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].

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.

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]

Missing source maps for large first-party JavaScript

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. [Learn more about source maps].

Elements with `role="dialog"` or `role="alertdialog"` do not have accessible names.

ARIA dialog elements without accessible names may prevent screen readers users from discerning the purpose of these elements. [Learn how to make ARIA dialog elements more accessible].

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].

Properly size images

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

Reduce initial server response time

Keep the server response time for the main document short because all other requests depend on it. [Learn more about the Time to First Byte metric].

LCP request discovery

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

Displays images with incorrect aspect ratio

Image display dimensions should match natural aspect ratio. [Learn more about image aspect ratio].

Third parties

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

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]

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