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Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

32

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
cdn.waterstones.com/bookjackets/large/9781/4721/9781472158352.jpg86400.0 s51.6 KiB
cdn.waterstones.com/bookjackets/large/9780/2418/9780241816264.jpg86400.0 s39.3 KiB
cdn.waterstones.com/bookjackets/large/9781/4059/9781405978415.jpg86400.0 s39.3 KiB
www.google-analytics.com/analytics.js7200.0 s20.9 KiB
cdn.waterstones.com/bookjackets/large/9780/2415/9780241517475.jpg86400.0 s39.2 KiB
www.dwin1.com/3787.js600.0 s16.1 KiB
cdn.waterstones.com/bookjackets/large/9781/5291/9781529157468.jpg86400.0 s35.8 KiB
cdn.waterstones.com/bookjackets/large/9780/0083/9780008384210.jpg86400.0 s30.2 KiB
cdn.waterstones.com/bookjackets/large/9780/5713/9780571378968.jpg86400.0 s29.9 KiB
cdn.waterstones.com/bookjackets/large/9780/0087/9780008742768.jpg86400.0 s26.3 KiB
cdn.waterstones.com/bookjackets/large/9781/8049/9781804941430.jpg86400.0 s25.0 KiB
cdn.waterstones.com/bookjackets/large/9781/3996/9781399624046.jpg86400.0 s21.7 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/...14400.0 s12.5 KiB
cdn.waterstones.com/bookjackets/large/9780/3494/9780349450612.jpg86400.0 s16.2 KiB
/cdn-cgi/challenge-platform/h/b/d/9f07b5e2e8c92a82/177689...0.0 ms3.3 KiB
www.waterstones.com/images/cover404.png14400.0 s4.0 KiB
cdn-cookieyes.com/assets/images/close.svg36000.0 s867 B
challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/cmg/10.0 ms208 B
/track.php?fingerprint=109741cd-dbed-403c-84f7-1ba637038b...0.0 ms170 B

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLEst Savings
static.waterstones.com/11.19.0/fonts/icomoon.woff?-o5tg7355 ms

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:318.044 source:map[column:26918 line:2 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:50.415 source:map[type:text value:[unattributed]]] map[reflowTime:0.548 source:map[column:49635 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:0.293 source:map[column:49697 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:0.299 source:map[column:49765 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:43.427 source:map[column:48923 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:0.412 source:map[column:50698 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:47.902 source:map[column:82691 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:0.722 source:map[column:29548 line:25 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:2.873 source:map[column:48945 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:75.437 source:map[column:52095 line:1 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:55.092 source:map[column:4444 line:27 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:35.216 source:map[column:52069 line:27 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:55.823 source:map[column:9385 line:27 type:source-location url:https://static.waterstones.com/11.19.0/js/bundle.js urlProvider:network]] map[reflowTime:44.18 source:map[column:100895 line:0 type:source-location url:https://cdn-cookieyes.com/client_data/7d1896a33bd53d40c20b3666/banner.js urlProvider:network]]]

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489898-780x650.jpeg134.3 KiB115.5 KiB
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489900-780x650.jpeg117.9 KiB99.1 KiB
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489894-780x650.jpeg102.3 KiB83.6 KiB
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489896-780x650.jpeg79.4 KiB61.3 KiB
div > div.span6 > a > img.ws-lazy div > div.span6 > a > img.ws-lazy
cdn.waterstones.com/images/00509343-561x434.jpeg68.5 KiB57.9 KiB
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00508272-770x513.jpeg74.0 KiB55.6 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9781/4721/9781472158352.jpg51.4 KiB48.9 KiB
div > div.span6 > a > img.ws-lazy div > div.span6 > a > img.ws-lazy
cdn.waterstones.com/images/00508474-561x434.jpeg52.5 KiB42.0 KiB
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00507435-770x513.jpeg58.7 KiB41.9 KiB
div > div.span6 > a > img.ws-lazy div > div.span6 > a > img.ws-lazy
cdn.waterstones.com/images/00508787-561x434.jpeg48.9 KiB38.4 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9780/2418/9780241816264.jpg39.1 KiB36.6 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9781/4059/9781405978415.jpg39.1 KiB36.6 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9780/2415/9780241517475.jpg39.0 KiB36.4 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v1/large/9780/2418/9780241831144.jpg36.4 KiB33.6 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9781/5291/9781529157468.jpg35.6 KiB33.0 KiB
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00509411-770x513.jpeg46.2 KiB33.0 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v2/large/9780/2416/9780241684450.jpg34.8 KiB32.2 KiB
Manga, Browse div.grid-images > a > div.feature-image > img
cdn.waterstones.com/images/00494718-400x393.jpeg35.5 KiB29.8 KiB
div > div.span6 > a > img.ws-lazy div > div.span6 > a > img.ws-lazy
cdn.waterstones.com/images/00508528-561x434.jpeg38.1 KiB28.0 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9780/0083/9780008384210.jpg30.0 KiB27.6 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9780/5713/9780571378968.jpg29.7 KiB27.2 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9780/0087/9780008742768.jpg26.0 KiB23.5 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9781/8049/9781804941430.jpg24.7 KiB22.4 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v2/large/2928/3773/2928377347765.jpg24.7 KiB22.2 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9781/3996/9781399624046.jpg21.5 KiB19.4 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v3/large/9780/0088/9780008808716.jpg21.5 KiB19.1 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v2/large/9781/8052/9781805229674.jpg20.9 KiB18.4 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v1/large/9781/5266/9781526678362.jpg20.4 KiB17.8 KiB
The Books You Always Meant to Read. Browse div.grid-images > a > div.feature-image > img
cdn.waterstones.com/images/00495138-400x393.jpeg19.5 KiB15.2 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/bookjackets/large/9780/3494/9780349450612.jpg16.0 KiB14.7 KiB
div.image-wrap > div.image-container > a > img.ws-lazy div.image-wrap > div.image-container > a > img.ws-lazy
cdn.waterstones.com/override/v2/large/9781/3994/9781399427210.jpg16.0 KiB13.6 KiB
Everyone's Talking About, Find Out More div.grid-images > a > div.feature-image > img
cdn.waterstones.com/images/00394650-400x393.jpeg17.2 KiB13.4 KiB
Book Deals, 50% Off RRP, Shop Now div.grid-images > a > div.feature-image > img
cdn.waterstones.com/images/00396598-400x393.jpeg16.4 KiB12.7 KiB
a > span > span.plus-pulse-icon > ::after a > span > span.plus-pulse-icon > ::after
static.waterstones.com/11.19.0/img/plus/plus-stamp.png9.2 KiB8.2 KiB
div.image-slider-container > a.image-slider-slide > div > img div.image-slider-container > a.image-slider-slide > div > img
cdn.waterstones.com/images/00444514-200x200.png4.9 KiB4.2 KiB

Each subpart has specific improvement strategies. Ideally, most of the LCP time should be spent on loading the resources, not within delays.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:label label:Subpart valueType:text] map[key:duration label:Duration valueType:ms]]
items: [map[duration:344.197 label:Time to first byte subpart:timeToFirstByte] map[duration:43.594 label:Resource load delay subpart:resourceLoadDelay] map[duration:187.932 label:Resource load duration subpart:resourceLoadDuration] map[duration:1940.28 label:Element render delay subpart:elementRenderDelay]]
lhId: page-35-IMG
nodeLabel: div > div.hero-slide > a > img.desktop-hide
path: 4,HTML,2,BODY,7,MAIN,2,DIV,1,DIV,2,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,A,1,IMG
selector: div > div.hero-slide > a > img.desktop-hide
snippet: <img class="desktop-hide tablet-hide mobile-show" srcset=" https://cdn.waterstones.com/images/00509411-420x280.jpeg 420w, …" src="https://cdn.waterstones.com/images/00509411-770x513.jpeg" sizes="100vw" alt="">

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-35-IMG
nodeLabel: div > div.hero-slide > a > img.desktop-hide
path: 4,HTML,2,BODY,7,MAIN,2,DIV,1,DIV,2,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,A,1,IMG
selector: div > div.hero-slide > a > img.desktop-hide
snippet: <img class="desktop-hide tablet-hide mobile-show" srcset=" https://cdn.waterstones.com/images/00509411-420x280.jpeg 420w, …" src="https://cdn.waterstones.com/images/00509411-770x513.jpeg" sizes="100vw" alt="">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
value: no origins were preconnected
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
static.waterstones.com/11.19.0/js/bundle.js211.9 KiB1.0 s
static.waterstones.com/11.19.0/js/ecommerce.js2.3 KiB
static.waterstones.com/11.19.0/css/bundle.css142.6 KiB1.8 s
cdn-cookieyes.com/client_data/7d1896a33bd53d40c20b3666/script.js34.3 KiB1.1 s

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 854 ms
URLTime Spent
waterstones.com/854 ms
www.waterstones.com/0.0 ms

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Diagnostics

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 26.5 KiB
URLTransfer SizeEst Savings
static.waterstones.com/11.19.0/css/bundle.css142.6 KiB26.5 KiB

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 670 ms 132.7 KiB
URLTransfer SizeEst Savings
static.waterstones.com/11.19.0/css/bundle.css142.3 KiB132.7 KiB

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.8 s 275.1 KiB
URLTransfer SizeEst Savings
static.waterstones.com/11.19.0/js/bundle.js211.8 KiB152.2 KiB
www.googletagmanager.com/gtag/js?id=G-P4C39TQPV3&cx=c&gtm=4e64k0153.0 KiB63.0 KiB
www.googletagmanager.com/gtm.js?id=GTM-N66L6Q141.8 KiB60.0 KiB

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTotal CPU TimeScript EvaluationScript Parse
static.waterstones.com/11.19.0/js/bundle.js2.7 s918 ms73 ms
www.waterstones.com/2.4 s279 ms26 ms
Unattributable645 ms39 ms0.0 ms
cdn-cookieyes.com/client_data/7d1896a33bd53d40c20b3666/script.js506 ms463 ms8.7 ms
www.waterstones.com/cdn-cgi/challenge-platform/scripts/jsd/main.js472 ms417 ms3.0 ms
cdn-cookieyes.com/client_data/7d1896a33bd53d40c20b3666/banner.js411 ms207 ms10 ms
www.googletagmanager.com/gtm.js?id=GTM-N66L6Q406 ms348 ms53 ms
js-agent.newrelic.com/nr-spa-1.313.1.min.js184 ms147 ms7.2 ms
www.googletagmanager.com/gtag/js?id=G-P4C39TQPV3&cx=c&gtm=4e64k0175 ms137 ms38 ms
static.waterstones.com/11.19.0/css/bundle.css73 ms0.0 ms0.0 ms
www.dwin1.com/3787.js58 ms52 ms4.4 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation3.1 s
Style & Layout2.2 s
Other1.8 s
Rendering392 ms
Parse HTML & CSS315 ms
Script Parsing & Compilation235 ms
Garbage Collection59 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
Pages with cache-control:no-store header cannot enter back/forward cache.Actionable
Pages that use WebXR are not currently eligible for back/forward cache.Actionable
Pages whose main resource has cache-control:no-store cannot enter back/forward cache.Not actionable
Back/forward cache is disabled because some JavaScript network request received resource with Cache-Control: no-store header.Not actionable

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:17768...294.8 KiB
static.waterstones.com/11.19.0/js/bundle.js211.9 KiB
www.googletagmanager.com/gtag/js?id=G-P4C39TQPV3&cx=c&gtm=4e64k0153.1 KiB
static.waterstones.com/11.19.0/css/bundle.css142.6 KiB
www.googletagmanager.com/gtm.js?id=GTM-N66L6Q142.2 KiB
cdn.waterstones.com/images/00489898-780x650.jpeg134.7 KiB
cdn.waterstones.com/images/00489900-780x650.jpeg118.2 KiB
cdn.waterstones.com/images/00489894-780x650.jpeg102.6 KiB
/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/1...97.6 KiB
cdn.waterstones.com/images/00489896-780x650.jpeg79.9 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489894-780x650.jpeg
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489900-780x650.jpeg
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489896-780x650.jpeg
div.swiper-slide > a > div.image-container > img div.swiper-slide > a > div.image-container > img
cdn.waterstones.com/images/00489898-780x650.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00508272-770x513.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00509411-770x513.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00507435-770x513.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00508272-770x513.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00509411-770x513.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00507435-770x513.jpeg
div > div.hero-slide > a > img.desktop-hide div > div.hero-slide > a > img.desktop-hide
cdn.waterstones.com/images/00508272-770x513.jpeg

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits
●Optimize DOM size
●Modern HTTP
●Optimize viewport for mobile
●Minify JavaScript
●User Timing marks and measures 7 user timings
●Avoid long main-thread tasks 20 long tasks found
●Network Requests
●Network Round Trip Times 40 ms
●Server Backend Latencies 110 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 210 ms
●Avoid large layout shifts 1 layout shift found
○INP breakdown
○Avoid non-composited animations
93

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

ARIA

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.

Why this matters

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Failing Elements
New Rebecca Yarros. Untitled Empyrean Not Book 4. 29.09.26.Pre-Orde div.hero-banner > div.slick-list > div.slick-track > div.slick-slide

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.

Best practices

Touch targets with sufficient size and spacing help users who may have difficulty targeting small controls to activate the targets. Learn more about touch targets.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Go to slide 1 div.hero-banner > ul.slick-dots > li > button
Rebecca Yarros div.info-wrap > div.author-wrap > span.authors > a.text-author
Andy Weir div.info-wrap > div.author-wrap > span.authors > a.text-author
Rebecca Yarros div.info-wrap > div.author-wrap > span.authors > a.text-author
Andy Weir div.info-wrap > div.author-wrap > span.authors > a.text-author
Rebecca Yarros div.info-wrap > div.author-wrap > span.authors > a.text-author
Charlie Mackesy div.info-wrap > div.author-wrap > span.authors > a.text-author
Mel Robbins div.info-wrap > div.author-wrap > span.authors > a.text-author
Jess Kidd div.info-wrap > div.author-wrap > span.authors > a.text-author
Jess Kidd div.info-wrap > div.author-wrap > span.authors > a.text-author
Andy Weir div.info-wrap > div.author-wrap > span.authors > a.text-author
Joe Dunthorne div.info-wrap > div.author-wrap > span.authors > a.text-author
Deborah Levy div.info-wrap > div.author-wrap > span.authors > a.text-author
Katie Kirby div.info-wrap > div.author-wrap > span.authors > a.text-author
Huw Aaron div.info-wrap > div.author-wrap > span.authors > a.text-author
Derek Landy div.info-wrap > div.author-wrap > span.authors > a.text-author
S. F. Williamson div.info-wrap > div.author-wrap > span.authors > a.text-author
Suzanne Collins div.info-wrap > div.author-wrap > span.authors > a.text-author

These items highlight common accessibility best practices.

○Interactive controls are keyboard focusable
○Interactive elements indicate their purpose and state
○The page has a logical tab order
○Visual order on the page follows DOM order
○User focus is not accidentally trapped in a region
○The user's focus is directed to new content added to the page
○HTML5 landmark elements are used to improve navigation
○Offscreen content is hidden from assistive technology
○Custom controls have associated labels
○Custom controls have ARIA roles
●`[aria-*]` attributes match their roles
●`[aria-hidden="true"]` is not present on the document `<body>`
●`[role]`s have all required `[aria-*]` attributes
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●Buttons have an accessible name
●Image elements have `[alt]` attributes
●Form elements have associated labels
●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
●`button`, `link`, and `menuitem` elements have accessible names
●ARIA attributes are used as specified for the element's role
●Elements use only permitted ARIA attributes
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links have a discernible name
●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
●No element has a `[tabindex]` value greater than 0
●Heading elements appear in a sequentially-descending order
●Skip links are focusable.
●Document has a main landmark.
●Deprecated ARIA roles were not used
●Identical links have the same purpose.
●Elements with visible text labels have matching accessible names.
○`[accesskey]` values are unique
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
○`[role]`s are contained by their required parent element
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○The page contains a heading, skip link, or landmark region
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<frame>` or `<iframe>` elements have a title
○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
○Input buttons have discernible text.
○`<input type="image">` elements have `[alt]` text
○Links are distinguishable without relying on color.
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
○`[lang]` attributes have a valid value
○`<video>` elements contain a `<track>` element with `[kind="captions"]`
○Tables have different content in the summary attribute and `<caption>`.
○All heading elements contain content.
○Uses ARIA roles only on compatible elements
○Image elements do not have `[alt]` attributes that are redundant text.
○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
○`<td>` elements in a large `<table>` have one or more table headers.
77

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
SharedStorage
www.waterstones.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.
www.waterstones.com/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge
www.waterstones.com/cdn-cgi/challenge-platform/scripts/jsd/main.js

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

SourceDescription
www.waterstones.com/manifest/webmanifest
Failed to load resource: the server responded with a status of 403 ()
www.waterstones.com/ line 17274, col 0
Manifest fetch from https://www.waterstones.com/manifest/webmanifest failed, code 403
www.waterstones.com/ line 11, col 8753
TurnstileError: [Cloudflare Turnstile] Error: 600010. at v (https://challenges.cloudflare.com/turnstile/v0/api.js:1:10922) at L (https://challenges.cloudflare.com/turnstile/v0/api.js:1:40040) at nrWrapper (https://www.waterstones.com/:12:8712)

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
static.waterstones.com/11.19.0/js/bundle.js
●Uses HTTPS
●Avoids third-party cookies
●Allows users to paste into input fields
●Avoids requesting the geolocation permission on page load
●Avoids requesting the notification permission on page load
●Displays images with correct aspect ratio
●Serves images with appropriate resolution
●Page has the HTML doctype
●Properly defines charset
●No issues in the `Issues` panel in Chrome Devtools
●Ensure CSP is effective against XSS attacks
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate DOM-based XSS with Trusted Types
●Detected JavaScript libraries
○Redirects HTTP traffic to HTTPS
○Mitigate clickjacking with XFO or CSP
82

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destinationLink Text
www.waterstones.com/books/bestsellersSEE MORE
www.waterstones.com/category/cultural-highlightsSEE MORE
www.waterstones.com/campaign/special-editionsSEE MORE
www.waterstones.com/campaign/coming-soonSEE MORE
www.waterstones.com/category/health-lifestyle/self-help-and-personal-developmentSEE MORE
www.waterstones.com/campaign/paperback-offersSEE MORE
www.waterstones.com/category/fictionSEE MORE
www.waterstones.com/non-fiction-booksSEE MORE
www.waterstones.com/booklist/788740/homepage-weekend-reviewsSEE MORE
www.waterstones.com/category/childrens-teenageSEE MORE
www.waterstones.com/category/childrens-teenage/facet/500SEE MORE
www.waterstones.com/category/stationery-giftsSEE MORE

Format your HTML in a way that enables crawlers to better understand your app’s content.

Crawling and Indexing

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Uncrawlable Link
… div.navs-container > ul.navs > li > a.nav-item-highlights
… div.navs-container > ul.navs > li > a.nav-item-fiction
… div.navs-container > ul.navs > li > a.nav-item-non-fiction
… div.navs-container > ul.navs > li > a.nav-item-children's
… div.navs-container > ul.navs > li > a.nav-item-stationery
… div.navs-container > ul.navs > li > a.nav-item-games
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li > a.nav-item-top
… li.subnav > ul.navs > li > a.nav-item-what's
… li.subnav > ul.navs > li > a.nav-item-favourite
… li.subnav > ul.navs > li > a.nav-item-favourite
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li > a.nav-item-top
… li.subnav > ul.navs > li > a.nav-item-fiction
… li.subnav > ul.navs > li > a.nav-item-crime
… li.subnav > ul.navs > li > a.nav-item-science
… li.subnav > ul.navs > li > a.nav-item-graphic
… li.subnav > ul.navs > li > a.nav-item-teenage
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li > a.nav-item-top
… li.subnav > ul.navs > li > a.nav-item-art
… li.subnav > ul.navs > li > a.nav-item-biography
… li.subnav > ul.navs > li > a.nav-item-history
… li.subnav > ul.navs > li > a.nav-item-home
… li.subnav > ul.navs > li > a.nav-item-nature
… li.subnav > ul.navs > li > a.nav-item-smart
… li.subnav > ul.navs > li > a.nav-item-spirituality
… li.subnav > ul.navs > li > a.nav-item-sport
… li.subnav > ul.navs > li > a.nav-item-travel
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li > a.nav-item-top
… li.subnav > ul.navs > li > a.nav-item-pre-school
… li.subnav > ul.navs > li > a.nav-item-children's
… li.subnav > ul.navs > li > a.nav-item-teenage
… li.subnav > ul.navs > li > a.nav-item-education
… li.subnav > ul.navs > li > a.nav-item-hobbies
… li.subnav > ul.navs > li > a.nav-item-stationery
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li > a.nav-item-gifts
… li.subnav > ul.navs > li > a.nav-item-children's
… li.subnav > ul.navs > li > a.nav-item-stationery
… li.subnav > ul.navs > li > a.nav-item-book
… li.subnav > ul.navs > li > a.nav-item-arts
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li > a.nav-item-games
… li.subnav > ul.navs > li.back > a.nav-item
… li.subnav > ul.navs > li.back > a.nav-item

To appear in search results, crawlers need access to your app.

○Structured data is valid
●Page isn’t blocked from indexing
●Document has a `<title>` element
●Document has a meta description
●Page has successful HTTP status code
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
○robots.txt is valid
○Document has a valid `rel=canonical`

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