C — https://iop.org | BeaverCheck Audit

Site Health

Score: 72 / 100

Based on 8 categories, 0 sections

Decent speed, but optimizing further could improve engagement.

Several missing protections leave your users and data exposed.

Several issues make your site difficult for assistive technology users.

Well-optimized for search — your content is discoverable.

Solid infrastructure — fast server responses across the board.

Strong compliance posture across regulations.

Good content signals with minor gaps.

Heavier than average — reducing page weight saves energy and bandwidth.

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

How the composite score is calculated

How you compare

Drupal · 171 peers

You 72

Avg 73

At average

0 50 100

Better than 21% of Drupal sites See full Drupal benchmark →

Amazon Route 53 · 545 peers

You 72

Avg 72

At average

0 50 100

Better than 33% of Amazon Route 53 sites See full Amazon Route 53 benchmark →

Top Priorities (5)

Content-Security-Policy header is missing

Security gaps expose your site and users to attacks, eroding trust.

Security › Security Headers

No Content-Security-Policy header found

Security gaps expose your site and users to attacks, eroding trust.

Security › Content Security Policy

Page weighs 12.6 MB (10.7 MB transferred)

Performance issues directly impact user engagement and conversion rates.

Performance › Page Weight Budget

1 control(s) without accessible label

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Form Accessibility

1 link(s) with no accessible text

Accessibility issues exclude users with disabilities — up to 15% of your potential audience.

Accessibility › Link & Button Quality

View fix priority matrix

Fix Priority Matrix

5 findings

Impact

Quick Wins

High impact, low effort — start here.

Strategic

High impact, requires investment.

Easy Improvements

Small gains, minimal effort.

Nothing in this quadrant — good news.

Deprioritize

Low impact, high effort — do last.

Nothing in this quadrant — good news.

← Low effort High effort →

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Markdown

[![BeaverCheck](https://beavercheck.com/badge?url=https%3A%2F%2Fiop.org)](https://beavercheck.com/results/8d7de4ee-4518-4c9b-be1e-b5c01bf95f5d)

HTML

<a href="https://beavercheck.com/results/8d7de4ee-4518-4c9b-be1e-b5c01bf95f5d"><img src="https://beavercheck.com/badge?url=https%3A%2F%2Fiop.org" alt="BeaverCheck Score"></a>

Image URL

https://beavercheck.com/badge?url=https%3A%2F%2Fiop.org

This badge auto-updates with your latest scan result.

What fixing these means

Your site performs reasonably well, but a few targeted fixes could meaningfully improve results. Your LCP of 27.7s exceeds Google's 2.5s 'Good' threshold and the 1 performance issue below directly contributes to it. Accessibility issues exclude users who rely on assistive technology — an estimated 15% of your potential audience. Addressing the critical issues below would have the most immediate impact on your user trust.

2 security gaps detected — browsers may warn visitors about your site.

Your LCP is 27.7s — fixing the 1 performance critical could bring it under Google's 2.5s 'Good' threshold.

2 accessibility issues exclude users who rely on assistive technology.

Conversion Barriers

2 critical 7 warning

9 barrier(s) likely increasing bounce by ~30%.

Speed (2)

Page takes 27.7s to load

+12% bounce

Users abandon at ~3s — you're 25.2s over the 2.5s threshold

Fix: Optimize render-blocking resources, preload the hero image, and compress images

High main-thread blocking time

+2% bounce

Page is non-interactive for 313ms after first paint

Fix: Defer third-party scripts and split large bundles

Trust (2)

No HSTS header

+1% bounce

Returning visitors are briefly exposed to downgrade attacks on first request

Fix: Set Strict-Transport-Security: max-age=31536000; includeSubDomains

No Content-Security-Policy header

+1% bounce

Higher XSS blast radius — one compromised script can exfiltrate the checkout form

Fix: Ship a reporting-only CSP first, then enforce once violations are clean

Usability (1)

1 form field(s) without a label

+2% bounce

Screen readers skip unlabeled fields; autofill can't identify them; checkout abandonment spikes

Fix: Associate every input with a visible <label for="…">; add autocomplete attributes

Content (2)

No structured data

+2% bounce

No rich-result eligibility in Google — lower SERP CTR vs competitors with stars and prices

Fix: Add JSON-LD for your page type (Product, Article, FAQPage, LocalBusiness, …)

Content is hard to read

+2% bounce

Graduate-level reading difficulty — limits the addressable audience for product or blog pages

Fix: Shorten sentences; replace jargon with plain language; target Flesch ease ≥60

Navigation (2)

47 link(s) with generic text ("click here", "read more")

+1% bounce

Screen-reader users navigating by link list see no context — and search engines can't infer relevance

Fix: Rewrite with descriptive phrases that identify the destination

85 broken link(s) on the page

+5% bounce

Clicks land on 404s — trust drops and the session often ends

Fix: Fix or remove the broken destinations surfaced on the Content tab

Preliminary CRO audit — each barrier links to the tab with detailed analysis.

Return on Investment

€510 investment → €2.50/month returns + EUR 120,500,000 risk avoided

Payback period: > 2 years First-year ROI: -94%

Investment

€510

6h · 5 findings

Monthly returns

€2.50 /mo

~€30 / year

Bandwidth savings €2.50

Regulatory risk avoided

EUR 120,500,000

if kept compliant

ePrivacy Directive EUR 100,000,000
GDPR EUR 20,000,000
EAA EUR 500,000

€85 — in quick wins — start here for the fastest payback

Figures combine localized regulatory fine ceilings, search/conversion value priced against local CPC, and bandwidth waste estimates. Results depend on implementation quality and audience composition. Not legal or financial advice.

Full methodology & sources

Estimated Remediation Cost

€510

6.0 developer hours at €85/hr

Based on European Union rates (€85/hr)

Quick wins

€85 2 fixes in ~60 minutes

Start here for the best return on investment

Cost by category

Cost by effort level

Adjust assumptions

Custom rate

€ /hr

Rates reflect fully-loaded developer cost including overhead

How developer rates are sourced

What Inaction Is Costing You

€10,041,669 / month at risk

~€120,500,030 / year if left unfixed

Compliance Risk

€120,500,000

ePrivacy DirectiveGDPREAA

No privacy policy link detected
GDPR: EUR 10,000 – EUR 20,000,000
Trackers detected but no cookie policy found
GDPR: EUR 5,000 – EUR 10,000,000
Trackers detected but no cookie policy found
GDPR: EUR 10,000 – EUR 20,000,000

+7 more

Bandwidth Waste

€2.50 /mo

33704.8 MB/mo × 0.074 EUR/GB

Optimize transfer: save ~3.4 MB per page load
Saves €2.50/mo

Compliance figures represent the statutory maximum fine for the most severe triggered category, capped per regulation — not the sum of per-finding penalties. Based on published regulatory fine ranges. This is not legal advice.

Compliance methodology · SEO assumptions · Bandwidth model

Your performance is already good — improvements may show diminishing returns

Monthly visitors

Unique monthly visitors from your analytics

Conversion rate (%)

Purchases, signups, or key actions

Avg. order value

Optional — for revenue estimation

additional conversions/month

more engaged visitors from reduced bounce

potential monthly revenue

Current bounce (est.)

After fixes (est.)

Estimated bounce reduction

Fix 5 critical issues to capture this value

How this is calculated

Based on Google/Deloitte research ("Milliseconds Make Millions") showing a ~7% bounce rate increase per additional second of LCP above the 2.5s "Good" threshold.

Your site's LCP: → estimated after fixes.

These are estimates based on industry research — actual results vary

Bounce-rate model & assumptions

Your data stays in your browser — nothing is sent to our servers

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Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

2.60 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

27.67 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

313 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

7.26 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

29.44 s

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

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Most users today run browsers that natively support ES6+, async/await, optional chaining, and the rest of modern JavaScript. Transpiling to ES5 'just in case' adds 20-40% to your bundle for no benefit. Configure your build to target a modern browserslist, or ship a differential bundle pair (modern + legacy) with the module/nomodule pattern.

Source: Google web.dev / Lighthouse

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.

Request	Cache TTL	Transfer Size
js.stripe.com/v3/	120.0 s	220.2 KiB
m.stripe.network/out-4.5.45.js	300.0 s	16.5 KiB
www.iop.org/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js?	14400.0 s	12.9 KiB

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.

URL	Est Savings
www.iop.org/themes/custom/iop_theme/build/fonts/icomoon.woff	45 ms

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.

	URL	Resource Size	Est Savings
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	2.5 MiB	2.4 MiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	1.3 MiB	1.2 MiB
LIMIT LESS Support young people to change the world Limit Less is our campaig… `div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero`	www.iop.org/sites/default/files/2020-10/limit-less-banner-2.jpg	1.7 MiB	1.1 MiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	798.6 KiB	750.2 KiB
INSTITUTE OF PHYSICS Events Events for the physics community across the UK an… `div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero`	www.iop.org/sites/default/files/2018-10/Environment%20and%20energy.jpg	540.2 KiB	377.4 KiB
Culture, history and society image `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	251.7 KiB	203.2 KiB
IOP.ORG Read more Artemis II: our journey to the Moon begins with physics 6 day… `div.field__item > div > div.iop-promo-block__multiple-fields > div.iop-promo-block`	www.iop.org/sites/default/files/2026-04/Artemis-II-lunar-flyby-with-Earth.jpg	599.7 KiB	165.8 KiB
An artist's view of what the gallery will look like in the Institute of Physics `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	199.0 KiB	159.5 KiB
INSTITUTE OF PHYSICS Become an IOP member Join a vibrant community of people … `div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero`	www.iop.org/sites/default/files/2019-02/membership-carousel.jpg	808.7 KiB	157.7 KiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	157.6 KiB	126.3 KiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	149.0 KiB	119.4 KiB
Crowd of people cheering `div.field > article.media > picture > img`	/sites/default/files/styles/component_hero_800_700/public...	86.0 KiB	39.0 KiB

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-12-DIV

nodeLabel: Institute of Physics We are the professional body and learned society for phys…

path: 1,HTML,1,BODY,2,DIV,0,DIV,1,DIV,1,ARTICLE,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,2,DIV,0,DIV

selector: div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero

snippet: <div class="iop-hero iop-hero--lg" style="background-image: url('/sites/default/files/2022-09/family-day-001.jpg')">

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.

URL	Transfer Size	Duration
www.iop.org/modules/contrib/google_tag/js/gtm.js?tdi04s	842 B
www.iop.org/modules/contrib/google_tag/js/gtag.js?tdi04s	1.1 KiB
/sites/default/files/js/js_b6LZj6c1gz5idt2o-8QkVwsK-lkMhF...	831 B
/sites/default/files/css/css_YKV4yw1vo42EOKrY3h8MkpEYYrV0...	63.9 KiB	332 ms
/sites/default/files/css/css_rAtmwcV-HJ3j1zmnwT5PIy0mraVM...	2.7 KiB

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.

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

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

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: 752 ms

URL	Time Spent
iop.org/	752 ms
www.iop.org/	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.

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 58.3 KiB

URL	Transfer Size	Est Savings
/sites/default/files/css/css_YKV4yw1vo42EOKrY3h8MkpEYYrV0...	63.7 KiB	58.3 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

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

This is the Lighthouse audit fired when too much JS is shipped relative to what executes. The fix isn't a config flag — it requires bundle analysis (webpack-bundle-analyzer, rollup-plugin-visualizer), splitting routes into chunks, lazy-loading off-screen components, and removing unused dependencies. Fundamentally different from minification: minifying reduces byte count, this reduces what's downloaded at all.

Source: Google web.dev / Lighthouse

Estimated savings: 1.7 s 353.5 KiB

URL	Transfer Size	Est Savings
js.stripe.com/v3/	219.8 KiB	159.9 KiB
/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc...	211.1 KiB	124.7 KiB
www.googletagmanager.com/gtm.js?id=GTM-53NVWC3	160.3 KiB	68.9 KiB

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.

URL	Transfer Size
/sites/default/files/styles/event_hero_1500x1000px/public...	2.5 MiB
www.iop.org/sites/default/files/2020-10/limit-less-banner-2.jpg	1.7 MiB
/sites/default/files/styles/event_hero_1500x1000px/public...	1.3 MiB
www.iop.org/sites/default/files/2019-02/membership-carousel.jpg	810.0 KiB
/sites/default/files/styles/event_hero_1500x1000px/public...	799.8 KiB
www.iop.org/sites/default/files/2026-04/Artemis-II-lunar-flyby-with-Earth.jpg	600.8 KiB
www.iop.org/sites/default/files/2022-09/family-day-001.jpg	590.0 KiB
www.iop.org/sites/default/files/2018-10/Environment%20and%20energy.jpg	541.0 KiB
/sites/default/files/2025-05/iop-mimi-adventure-family-da...	353.5 KiB
/sites/default/files/styles/event_hero_1500x1000px/public...	252.2 KiB

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

●Layout shift culprits

●Optimize DOM size

●Forced reflow

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Minify CSS

●Minify JavaScript

●JavaScript execution time 1.1 s

●Minimizes main-thread work 2.0 s

●Avoid long main-thread tasks 6 long tasks found

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 170 ms

●Server Backend Latencies 30 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 220 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○User Timing marks and measures

○Avoid non-composited animations

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

Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more about roles and required attributes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Events `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Support young people to change the world `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Institute of Physics `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Become an IOP member `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Events `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Support young people to change the world `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Institute of Physics `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Become an IOP member `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`

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.

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
Pagination `div.view > div.iop-filtered-content__pager > nav > h4#pagination-heading`

These are opportunities to improve keyboard navigation in your application.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html.js `html.js`

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]` 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

●`[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

●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

●Touch targets have sufficient size and spacing.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[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

○Form elements have associated labels

○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>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

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

○Elements with visible text labels have matching accessible names.

○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

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 / Warning	Source
SharedStorage	www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.	www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge	www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js

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
/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc...

●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 browser errors logged to the console

●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

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 destination	Link Text
www.iop.org/about/news/open-letter-science-minister-heads-physics	Read more
/about/news/iop-extends-cautious-welcome-government-plans...	Read more
www.iop.org/about/news/chief-executive-iop-comments-270000-fine	Read more
www.iop.org/about/news/welcome-government-commitment-to-fusion-energy	Read more
www.iop.org/about/news/partnership-to-boost-quantum-tech-start-ups	Read more
www.iop.org/about/news/response-government-plan-quantum	Read more
www.iop.org/about/news/iop-welcomes-news-on-national-photonics-strategy	Read more
www.iop.org/about/news/michele-dougherty-steps-down-as-iop-president	Read more
www.iop.org/about/news/open-letter-science-minister-heads-physics	Read more
/about/news/iop-extends-cautious-welcome-government-plans...	Read more
www.iop.org/about/news/chief-executive-iop-comments-270000-fine	Read more
www.iop.org/about/news/welcome-government-commitment-to-fusion-energy	Read more
www.iop.org/about/blogs/artemis-ii-moon-journey-begins-with-physics	Read more
www.iop.org/explore-physics/mimis-tiny-adventure/teacher-guide	Read more
/events/openflexure-microscope-3d-printed-microscope-teac...	Read more
www.iop.org/events/topological-physics-condensed-matter	Read more
/events/why-neutronium-not-part-everyday-matter-and-why-d...	Read more
/events/3-minute-wonder-science-communication-competition...	Read more
www.iop.org/events/ocean-hydrothermal-vents-and-rare-earths-conundrum	Read more
www.iop.org/events/hucknall-flight-test-museum-visit	Read more
www.iop.org/events/become-iop-fellow-finstp-1	Read more
/events/uk-nuclear-energy-dealing-challenges-last-70-year...	Read more
/events/openflexure-microscope-3d-printed-microscope-teac...	Read more
www.iop.org/events/topological-physics-condensed-matter	Read more
/events/why-neutronium-not-part-everyday-matter-and-why-d...	Read more
/events/3-minute-wonder-science-communication-competition...	Read more
/strategy/science-innovation/medical-physics-uk-impact-pr...	Read more
www.iop.org/node/9401	Read more
www.iop.org/about/news/chief-executive-iop-comments-270000-fine	Read more
www.iop.org/about/news/welcome-government-commitment-to-fusion-energy	Read more
www.iop.org/about/blogs/artemis-ii-moon-journey-begins-with-physics	Read more
www.iop.org/explore-physics/mimis-tiny-adventure/teacher-guide	Read more
www.iop.org/about/news/partnership-to-boost-quantum-tech-start-ups	Read more
www.iop.org/node/9399	Read more

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

○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 are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

Performance

Accessibility

Best Practices

SEO

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

676 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

2.23 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.059

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.83 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

2.23 s

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.

Why this matters

Shipping ES5 transpiled code to modern browsers wastes bytes — every user with an evergreen browser pays for compatibility you don't need.

Learn more ▾

Source: Google web.dev / Lighthouse

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.

Request	Cache TTL	Transfer Size
js.stripe.com/v3/	120.0 s	220.2 KiB
m.stripe.network/out-4.5.45.js	300.0 s	16.5 KiB
www.iop.org/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js?	14400.0 s	13.8 KiB

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.

URL	Est Savings
www.iop.org/themes/custom/iop_theme/build/fonts/icomoon.woff	75 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:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]

items: [map[reflowTime:67.614 source:map[type:text value:[unattributed]]] map[reflowTime:0.675 source:map[column:50335 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:0.229 source:map[column:50393 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:0.199 source:map[column:50457 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:0.28 source:map[column:79427 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:4.464 source:map[column:43932 line:62 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:1.198 source:map[column:49615 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:0.304 source:map[column:51395 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V urlProvider:network]] map[reflowTime:0.057 source:map[column:49637 line:2 type:source-location url:https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V 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.

	URL	Resource Size	Est Savings
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	2.5 MiB	2.5 MiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	1.3 MiB	1.3 MiB
LIMIT LESS Support young people to change the world Limit Less is our campaig… `div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero`	www.iop.org/sites/default/files/2020-10/limit-less-banner-2.jpg	1.7 MiB	1.1 MiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	798.6 KiB	788.0 KiB
INSTITUTE OF PHYSICS Events Events for the physics community across the UK an… `div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero`	www.iop.org/sites/default/files/2018-10/Environment%20and%20energy.jpg	540.2 KiB	377.4 KiB
Culture, history and society image `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	251.7 KiB	241.1 KiB
An artist's view of what the gallery will look like in the Institute of Physics `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	199.0 KiB	190.3 KiB
IOP.ORG Read more Artemis II: our journey to the Moon begins with physics 6 day… `div.field__item > div > div.iop-promo-block__multiple-fields > div.iop-promo-block`	www.iop.org/sites/default/files/2026-04/Artemis-II-lunar-flyby-with-Earth.jpg	599.7 KiB	165.8 KiB
INSTITUTE OF PHYSICS Become an IOP member Join a vibrant community of people … `div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero`	www.iop.org/sites/default/files/2019-02/membership-carousel.jpg	808.7 KiB	157.7 KiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	157.6 KiB	150.8 KiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	125.5 KiB	120.0 KiB
li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px `li.iop-content-listing-carousel__carousel-list-item > div.iop-media-block > div.iop-media-block__media > img.image-style-event-hero-1500x1000px`	/sites/default/files/styles/event_hero_1500x1000px/public...	149.0 KiB	40.5 KiB

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-12-DIV

nodeLabel: Institute of Physics We are the professional body and learned society for phys…

path: 1,HTML,1,BODY,2,DIV,0,DIV,1,DIV,1,ARTICLE,1,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,2,DIV,0,DIV

selector: div.glide__track > div.glide__slides > div.iop-impact-centre-carousel-slide > div.iop-hero

snippet: <div class="iop-hero iop-hero--lg" style="background-image: url('/sites/default/files/2022-09/family-day-001.jpg')">

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.

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

value: No additional origins are good candidates for preconnecting

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.

URL	Transfer Size	Duration
www.iop.org/modules/contrib/google_tag/js/gtag.js?tdi04s	928 B
/sites/default/files/css/css_YKV4yw1vo42EOKrY3h8MkpEYYrV0...	63.9 KiB	113 ms
www.iop.org/modules/contrib/google_tag/js/gtm.js?tdi04s	999 B
/sites/default/files/js/js_b6LZj6c1gz5idt2o-8QkVwsK-lkMhF...	504 B
/sites/default/files/css/css_rAtmwcV-HJ3j1zmnwT5PIy0mraVM...	2.7 KiB

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.

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

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: 60 ms 57.0 KiB

URL	Transfer Size	Est Savings
/sites/default/files/css/css_YKV4yw1vo42EOKrY3h8MkpEYYrV0...	63.7 KiB	57.0 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

Multi-megabyte JavaScript bundles delay every interactive feature on the page.

Learn more ▾

Source: Google web.dev / Lighthouse

Estimated savings: 260 ms 353.5 KiB

URL	Transfer Size	Est Savings
js.stripe.com/v3/	219.8 KiB	159.9 KiB
/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc...	211.1 KiB	124.7 KiB
www.googletagmanager.com/gtm.js?id=GTM-53NVWC3	160.3 KiB	68.9 KiB

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.

URL	Transfer Size
/sites/default/files/styles/event_hero_1500x1000px/public...	2.5 MiB
www.iop.org/sites/default/files/2020-10/limit-less-banner-2.jpg	1.7 MiB
/sites/default/files/styles/event_hero_1500x1000px/public...	1.3 MiB
www.iop.org/sites/default/files/2019-02/membership-carousel.jpg	810.0 KiB
/sites/default/files/styles/event_hero_1500x1000px/public...	799.8 KiB
www.iop.org/sites/default/files/2026-04/Artemis-II-lunar-flyby-with-Earth.jpg	601.0 KiB
www.iop.org/sites/default/files/2022-09/family-day-001.jpg	590.0 KiB
www.iop.org/sites/default/files/2018-10/Environment%20and%20energy.jpg	541.2 KiB
/sites/default/files/2025-05/iop-mimi-adventure-family-da...	353.5 KiB
/sites/default/files/styles/event_hero_1500x1000px/public...	252.5 KiB

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

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: 237 ms

URL	Time Spent
iop.org/	237 ms
www.iop.org/	0.0 ms

●Time to Interactive 2.2 s

●Layout shift culprits

●Optimize DOM size

●LCP breakdown

●Modern HTTP

●Optimize viewport for mobile

●Max Potential First Input Delay 50 ms

●Minify CSS

●Minify JavaScript

●JavaScript execution time 0.2 s

●Minimizes main-thread work 0.5 s

●Image elements have explicit `width` and `height`

●Page didn't prevent back/forward cache restoration

●Network Requests

●Network Round Trip Times 180 ms

●Server Backend Latencies 20 ms

●Tasks

●Diagnostics

●Metrics

●Screenshot Thumbnails

●Final Screenshot

●Script Treemap Data

●Resources Summary

●Initial server response time was short Root document took 270 ms

●Avoid large layout shifts 1 layout shift found

○INP breakdown

○User Timing marks and measures

○Avoid long main-thread tasks

○Avoid non-composited animations

Accessibility

ARIA

Some ARIA roles have required attributes that describe the state of the element to screen readers. Learn more about roles and required attributes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Events `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Support young people to change the world `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Institute of Physics `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Become an IOP member `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Events `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Support young people to change the world `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Institute of Physics `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`
Become an IOP member `div.iop-impact-centre-carousel-slide > div.iop-hero > div.iop-impact-centre-carousel-slide__content > div.iop-impact-centre-carousel-slide__heading`

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.

Navigation

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
Pagination `div.view > div.iop-filtered-content__pager > nav > h4#pagination-heading`

These are opportunities to improve keyboard navigation in your application.

Best practices

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html.js `html.js`

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]` 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

●`[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

●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

●Touch targets have sufficient size and spacing.

●Deprecated ARIA roles were not used

●Identical links have the same purpose.

○`[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

○Form elements have associated labels

○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>`.

○All heading elements contain content.

○Uses ARIA roles only on compatible elements

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

○Elements with visible text labels have matching accessible names.

○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

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 / Warning	Source
SharedStorage	www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.	www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge	www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc...

●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 browser errors logged to the console

●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

SEO

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 destination	Link Text
www.iop.org/about/news/partnership-to-boost-quantum-tech-start-ups	Read more
www.iop.org/about/news/response-government-plan-quantum	Read more
www.iop.org/about/news/iop-welcomes-news-on-national-photonics-strategy	Read more
www.iop.org/about/news/michele-dougherty-steps-down-as-iop-president	Read more
www.iop.org/about/news/open-letter-science-minister-heads-physics	Read more
/about/news/iop-extends-cautious-welcome-government-plans...	Read more
www.iop.org/about/news/chief-executive-iop-comments-270000-fine	Read more
www.iop.org/about/news/welcome-government-commitment-to-fusion-energy	Read more
www.iop.org/about/news/partnership-to-boost-quantum-tech-start-ups	Read more
www.iop.org/about/news/response-government-plan-quantum	Read more
www.iop.org/about/news/iop-welcomes-news-on-national-photonics-strategy	Read more
www.iop.org/about/news/michele-dougherty-steps-down-as-iop-president	Read more
www.iop.org/about/news/open-letter-science-minister-heads-physics	Read more
/about/news/iop-extends-cautious-welcome-government-plans...	Read more
www.iop.org/about/news/chief-executive-iop-comments-270000-fine	Read more
www.iop.org/about/news/welcome-government-commitment-to-fusion-energy	Read more
www.iop.org/about/news/partnership-to-boost-quantum-tech-start-ups	Read more
www.iop.org/about/news/response-government-plan-quantum	Read more
www.iop.org/about/news/iop-welcomes-news-on-national-photonics-strategy	Read more
www.iop.org/about/news/michele-dougherty-steps-down-as-iop-president	Read more
www.iop.org/about/blogs/artemis-ii-moon-journey-begins-with-physics	Read more
www.iop.org/explore-physics/mimis-tiny-adventure/teacher-guide	Read more
www.iop.org/events/ocean-hydrothermal-vents-and-rare-earths-conundrum	Read more
www.iop.org/events/hucknall-flight-test-museum-visit	Read more
www.iop.org/events/become-iop-fellow-finstp-1	Read more
/events/uk-nuclear-energy-dealing-challenges-last-70-year...	Read more
/events/openflexure-microscope-3d-printed-microscope-teac...	Read more
www.iop.org/events/topological-physics-condensed-matter	Read more
/events/why-neutronium-not-part-everyday-matter-and-why-d...	Read more
/events/3-minute-wonder-science-communication-competition...	Read more
www.iop.org/events/ocean-hydrothermal-vents-and-rare-earths-conundrum	Read more
www.iop.org/events/hucknall-flight-test-museum-visit	Read more
www.iop.org/events/become-iop-fellow-finstp-1	Read more
/events/uk-nuclear-energy-dealing-challenges-last-70-year...	Read more
/events/openflexure-microscope-3d-printed-microscope-teac...	Read more
www.iop.org/events/topological-physics-condensed-matter	Read more
/events/why-neutronium-not-part-everyday-matter-and-why-d...	Read more
/events/3-minute-wonder-science-communication-competition...	Read more
www.iop.org/events/ocean-hydrothermal-vents-and-rare-earths-conundrum	Read more
www.iop.org/events/hucknall-flight-test-museum-visit	Read more
www.iop.org/events/become-iop-fellow-finstp-1	Read more
/events/uk-nuclear-energy-dealing-challenges-last-70-year...	Read more
/strategy/science-innovation/medical-physics-uk-impact-pr...	Read more
www.iop.org/node/9401	Read more
www.iop.org/about/news/chief-executive-iop-comments-270000-fine	Read more
www.iop.org/about/news/welcome-government-commitment-to-fusion-energy	Read more
www.iop.org/about/blogs/artemis-ii-moon-journey-begins-with-physics	Read more
www.iop.org/explore-physics/mimis-tiny-adventure/teacher-guide	Read more
www.iop.org/about/news/partnership-to-boost-quantum-tech-start-ups	Read more
www.iop.org/node/9399	Read more

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

○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 are crawlable

●robots.txt is valid

●Image elements have `[alt]` attributes

●Document has a valid `hreflang`

●Document has a valid `rel=canonical`

Results for https://iop.org

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Speed (2)

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Content (2)

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Best Practices

General

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