Lighthouse Mobile

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

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Detailed Report

Audit breakdown by category with detailed findings.

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.

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.

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:0.921 source:map[column:102592 line:2 type:source-location url:https://dd.thetrainline.com/tags.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:59.911 source:map[type:text value:[unattributed]]] map[reflowTime:0.702 source:map[column:86186 line:1 type:source-location url:https://dd.thetrainline.com/tags.js urlProvider:network]] map[reflowTime:0.219 source:map[column:86227 line:1 type:source-location url:https://dd.thetrainline.com/tags.js urlProvider:network]] map[reflowTime:2.466 source:map[column:402001 line:1 type:source-location url:https://www.thetrainline.com/public/hweb/js/vendors.3dca4dc4707fd5fd9fe2.mjs urlProvider:network]]]

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.

More than 4 preconnect connections were found. These should be used sparingly and only to the most important origins.

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

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

value: No additional origins are good candidates for preconnecting

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.

Request	Cache TTL	Transfer Size
dd.thetrainline.com/tags.js	3600.0 s	39.4 KiB
cdn.branch.io/branch-latest.min.js	300.0 s	23.5 KiB
widget.trustpilot.com/trustboxes/54ad5defc6454f065c28af8b/main.js	86400.0 s	17.9 KiB
widget.trustpilot.com/bootstrap/v5/tp.widget.bootstrap.min.js	86400.0 s	8.1 KiB

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: 1.9 s

URL	Time Spent
thetrainline.com/	878 ms
www.thetrainline.com/	980 ms
www.thetrainline.com/en-us	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

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: 330 ms 48.4 KiB

URL	Transfer Size	Est Savings
www.thetrainline.com/public/hweb/css/Home.8e552164d960dfbcba4e.css	32.4 KiB	27.5 KiB
www.thetrainline.com/public/hweb/css/vendors.4b534df22c53362b537c.css	24.9 KiB	20.9 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.

URL	Total CPU Time	Script Evaluation	Script Parse
www.thetrainline.com/public/hweb/js/Home.0f671f5c62979ec33431.mjs	2.3 s	1.3 s	153 ms
www.thetrainline.com/en-us	1.5 s	244 ms	53 ms
www.thetrainline.com/public/hweb/js/vendors.3dca4dc4707fd5fd9fe2.mjs	619 ms	335 ms	223 ms
www.thetrainline.com/public/hweb/js/app.3186b531f11c9cd28b70.mjs	587 ms	572 ms	14 ms
Unattributable	536 ms	48 ms	0.0 ms
www.googletagmanager.com/gtm.js?id=GTM-NJRBF7N	314 ms	249 ms	63 ms
dd.thetrainline.com/tags.js	223 ms	179 ms	10 ms
/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31...	182 ms	122 ms	53 ms
js-agent.newrelic.com/nr-spa-1.313.1.min.js	172 ms	138 ms	8.1 ms
/public/hweb/js/intl-Leisure-locales-en-US-asyncMessages-...	164 ms	153 ms	0.7 ms
cdn.branch.io/branch-latest.min.js	117 ms	102 ms	9.5 ms
securepubads.g.doubleclick.net/tag/js/gpt.js	79 ms	69 ms	9.2 ms
www.thetrainline.com/public/hweb/js/Modals-home.9bd7a2f959e2a2c40591.mjs	61 ms	43 ms	18 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.

Category	Time Spent
Script Evaluation	3.7 s
Other	1.2 s
Rendering	685 ms
Style & Layout	655 ms
Script Parsing & Compilation	636 ms
Garbage Collection	101 ms
Parse HTML & CSS	89 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 reason	Failure type
Pages with cache-control:no-store header cannot enter 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

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: 0.0 ms 906.0 KiB

URL	Transfer Size	Est Savings
www.thetrainline.com/public/hweb/js/Home.0f671f5c62979ec33431.mjs	605.4 KiB	348.1 KiB
www.thetrainline.com/public/hweb/js/vendors.3dca4dc4707fd5fd9fe2.mjs	645.6 KiB	336.8 KiB
/pagead/managed/js/gpt/m202604170101/pubads_impl.js?cb=31...	187.4 KiB	144.9 KiB
www.googletagmanager.com/gtm.js?id=GTM-NJRBF7N	194.0 KiB	76.2 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
ticket `li.vGVGl4mXM1bLiES9JH5x > div.Tz7k7EVAOzoILcOnqgqb > div.J1CXK5Y_oDYlhPWTxkeO > img.ktByu183QUy0kUte53Dw`	static.trainlinecontent.com/content/WEB/images/partnerships/train.svg
bookingDotCom `li.vGVGl4mXM1bLiES9JH5x > a.Tz7k7EVAOzoILcOnqgqb > div.J1CXK5Y_oDYlhPWTxkeO > img.ktByu183QUy0kUte53Dw`	static.trainlinecontent.com/content/WEB/images/partnerships/bed.svg
getYourGuide `li.vGVGl4mXM1bLiES9JH5x > a.Tz7k7EVAOzoILcOnqgqb > div.J1CXK5Y_oDYlhPWTxkeO > img.ktByu183QUy0kUte53Dw`	static.trainlinecontent.com/content/WEB/images/partnerships/castle.svg

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

●Layout shift culprits

●Optimize DOM size

●Font display

●Improve image delivery

●LCP breakdown

●Modern HTTP

●Render blocking requests

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●Avoids enormous network payloads Total size was 2,219 KiB

●User Timing marks and measures 15 user timings

●Avoid long main-thread tasks 15 long tasks found

●Avoid non-composited animations 2 animated elements found

●Network Requests

●Network Round Trip Times 60 ms

●Server Backend Latencies 140 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 470 ms

●Avoid large layout shifts 15 layout shifts found

○INP breakdown

○LCP request discovery

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.

Navigation

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Tickets `div.Tz7k7EVAOzoILcOnqgqb > div.PXHplFjoHiTbACoAwlEH > div > h4.K45yGYbSC7MyiA6M9a3V`

These are opportunities to improve keyboard navigation in your application.

Names and labels

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
div.vrf33QMko7ORTI93hIAz > div.scoped-app-store-icons > div.app-store-icons > a.app-store-icon `div.vrf33QMko7ORTI93hIAz > div.scoped-app-store-icons > div.app-store-icons > a.app-store-icon`
div.vrf33QMko7ORTI93hIAz > div.scoped-app-store-icons > div.app-store-icons > a.app-store-icon `div.vrf33QMko7ORTI93hIAz > div.scoped-app-store-icons > div.app-store-icons > a.app-store-icon`

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Stays Booking.com `div.LFHk7aeRbwREGGIzsZy6 > div.EYvcisANXjYMsH4CuUY8 > li.vGVGl4mXM1bLiES9JH5x > a.Tz7k7EVAOzoILcOnqgqb`
Attractions GetYourGuide `div.LFHk7aeRbwREGGIzsZy6 > div.EYvcisANXjYMsH4CuUY8 > li.vGVGl4mXM1bLiES9JH5x > a.Tz7k7EVAOzoILcOnqgqb`

○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

●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

●`[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

●`[aria-hidden="true"]` elements do not contain focusable descendents

●ARIA input fields have accessible names

●Elements use only permitted ARIA attributes

●ARIA toggle fields have accessible names

●Background and foreground colors have a sufficient contrast ratio

●Document has a `<title>` element

●`<frame>` or `<iframe>` elements have a title

●`<html>` element has a `[lang]` attribute

●`<html>` element has a valid value for its `[lang]` attribute

●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

●Touch targets have sufficient size and spacing.

●Document has a main landmark.

●Deprecated ARIA roles were not used

●ARIA IDs are unique

●All heading elements contain content.

●Uses ARIA roles only on compatible elements

○`[accesskey]` values are unique

○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.

○ARIA `meter` elements have accessible names

○ARIA `progressbar` elements have accessible names

○Elements with the `role=text` attribute do not have focusable descendents.

○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

○No form fields have multiple labels

○`<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.

○Skip links are focusable.

○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>`.

○Image elements do not have `[alt]` attributes that are redundant text.

○Identical links have the same purpose.

○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.

Best Practices

General

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.

Source	Description
www.thetrainline.com/api/basket?nocreate=1	`Failed to load resource: the server responded with a status of 404 ()`

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	Map URL
www.thetrainline.com/public/hweb/js/vendors.3dca4dc4707fd5fd9fe2.mjs
www.thetrainline.com/public/hweb/js/Home.0f671f5c62979ec33431.mjs
widget.trustpilot.com/bootstrap/v5/tp.widget.bootstrap.min.js	widget.trustpilot.com/bootstrap/v5/tp.widget.bootstrap.min.js.map

●Uses HTTPS

●Avoids deprecated APIs

●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

100

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.

○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

●Links have descriptive text

●Links are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`