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concat-one.html
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<!DOCTYPE html>
<html lang=en-GB class="page page--home ">
<meta charset=UTF-8>
<meta name=viewport content="width=device-width, minimum-scale=1.0">
<title>Site-Speed and Web Performance Engineering – CSS Wizardry – Web Performance Optimisation</title>
<link rel=preconnect href=https://res.cloudinary.com>
<link rel=preconnect href=https://cdn.carbonads.com>
<link rel=preconnect href=https://srv.carbonads.net>
<link rel=preconnect href=https://cdn.syndication.twimg.com>
<link rel=preconnect href=https://syndication.twitter.com>
<link rel=preconnect href=https://csswizardry.com crossorigin>
<script>
window.ga=window.ga||function(){(ga.q=ga.q||[]).push(arguments)};ga.l=+new Date;
ga('create', 'UA-1856861-4', {'siteSpeedSampleRate': 100});
ga('send', 'pageview');
</script>
<script>
LUX=(function(){var a=("undefined"!==typeof(LUX)&&"undefined"!==typeof(LUX.gaMarks)?LUX.gaMarks:[]);var d=("undefined"!==typeof(LUX)&&"undefined"!==typeof(LUX.gaMeasures)?LUX.gaMeasures:[]);var j="LUX_start";var k=window.performance;var l=("undefined"!==typeof(LUX)&&LUX.ns?LUX.ns:(Date.now?Date.now():+(new Date())));if(k&&k.timing&&k.timing.navigationStart){l=k.timing.navigationStart}function f(){if(k&&k.now){return k.now()}var o=Date.now?Date.now():+(new Date());return o-l}function b(n){if(k){if(k.mark){return k.mark(n)}else{if(k.webkitMark){return k.webkitMark(n)}}}a.push({name:n,entryType:"mark",startTime:f(),duration:0});return}function m(p,t,n){if("undefined"===typeof(t)&&h(j)){t=j}if(k){if(k.measure){if(t){if(n){return k.measure(p,t,n)}else{return k.measure(p,t)}}else{return k.measure(p)}}else{if(k.webkitMeasure){return k.webkitMeasure(p,t,n)}}}var r=0,o=f();if(t){var s=h(t);if(s){r=s.startTime}else{if(k&&k.timing&&k.timing[t]){r=k.timing[t]-k.timing.navigationStart}else{return}}}if(n){var q=h(n);if(q){o=q.startTime}else{if(k&&k.timing&&k.timing[n]){o=k.timing[n]-k.timing.navigationStart}else{return}}}d.push({name:p,entryType:"measure",startTime:r,duration:(o-r)});return}function h(n){return c(n,g())}function c(p,o){for(i=o.length-1;i>=0;i--){var n=o[i];if(p===n.name){return n}}return undefined}function g(){if(k){if(k.getEntriesByType){return k.getEntriesByType("mark")}else{if(k.webkitGetEntriesByType){return k.webkitGetEntriesByType("mark")}}}return a}return{mark:b,measure:m,gaMarks:a,gaMeasures:d}})();LUX.ns=(Date.now?Date.now():+(new Date()));LUX.ac=[];LUX.cmd=function(a){LUX.ac.push(a)};LUX.init=function(){LUX.cmd(["init"])};LUX.send=function(){LUX.cmd(["send"])};LUX.addData=function(a,b){LUX.cmd(["addData",a,b])};LUX_ae=[];window.addEventListener("error",function(a){LUX_ae.push(a)});LUX_al=[];if("function"===typeof(PerformanceObserver)&&"function"===typeof(PerformanceLongTaskTiming)){var LongTaskObserver=new PerformanceObserver(function(c){var b=c.getEntries();for(var a=0;a<b.length;a++){var d=b[a];LUX_al.push(d)}});try{LongTaskObserver.observe({type:["longtask"]})}catch(e){}};
LUX = window.LUX || {};
LUX.samplerate = 100;
LUX.label = 'Home';
</script>
<link rel=stylesheet href=/css/concat/bundle.css>
<script>
const css_time = performance.mark('css_time');
console.log(css_time.startTime)
</script>
<style>
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*
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<h1 class=page-head__text id=heading>Web Performance Optimisation, Consultancy, and Engineering</h1>
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<p><strong style="display: block;">Your website is slow. I know
why.</strong> Web performance is big business for any industry: from
recouping lost sales to increasing conversions; reducing running costs
to user retention; better SEO to lowering your environmental impact.
Let’s work together to identify and fix your blind-spots.</p>
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<p><strong style="display: block;">What is your web performance
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experts. Never run slowly again.</p>
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<blockquote class="pull-quote pull-quote--banner">
<p>Harry gave the team a strong footing for identifying performance issues on iPlayer. With his knowledge, we were able to roll out quick fixes to our audiences without the need for big rewrites, all within just two days.</p>
<b class=pull-quote__source><a href=https://twitter.com/mattjburrows>Matthew Burrows</a>, BBC iPlayer</b>
</blockquote>
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<blockquote class="pull-quote pull-quote--banner">
<p>Harry helped our team level up their scalable CSS architecture skills, and to say that he had a large impact on our work is an understatement. We can’t recommend him enough.</p>
<b class=pull-quote__source><a href=https://twitter.com/addyosmani>Addy Osmani</a>, Google</b>
</blockquote>
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<blockquote class="pull-quote pull-quote--banner">
<p>Harry’s workshop was excellent; we left with tons of new ideas and techniques to improve both the CSS architecture and overall performance of <a href="http://behance.com/" class="c-carousel__link">Behance</a> and <a href="http://myportfolio.com/" class="c-carousel__link">Adobe Portfolio</a>.</p>
<b class=pull-quote__source><a href=http://jackiebalzer.com/>Jackie Balzer</a>, Adobe</b>
</blockquote>
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<li class=c-carousel__pane>
<blockquote class="pull-quote pull-quote--banner">
<p>There’s a short list of people I whole-heartedly recommend for detailed performance work; Harry is right up there at the top.</p>
<b class=pull-quote__source><a href=https://timkadlec.com/>Tim Kadlec</a></b>
</blockquote>
</li>
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<blockquote class="pull-quote pull-quote--banner">
<p>The CSS architecture I learned from Harry on <a href="/case-studies/nhs-nhsx-elearning-platform/" class="c-carousel__link">the NHS project</a> has changed the way I work. Bravo!</p>
<b class=pull-quote__source><a href=https://twitter.com/joshnesbitt>Josh Nesbitt</a></b>
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<h3 class=heading>Articles</h3>
<p>There are <b>238</b> articles on this blog.
Find them all on the <a href="/archive/">archive page</a>.</p>
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<li class=list-ui__item>
<link rel=prerender href="/2023/07/in-defence-of-domcontentloaded/" />
<time class="post__date" datetime="2023-07-01">1 July, 2023</time>
<h3 class="post__title"><a href="/2023/07/in-defence-of-domcontentloaded/">In Defence of DOMContentLoaded</a></h3>
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<time class="post__date" datetime="2023-06-07">7 June, 2023</time>
<h3 class="post__title"><a href="/2023/06/site-speed-topography-remapped/">Site-Speed Topography Remapped</a></h3>
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<li class=list-ui__item>
<time class="post__date" datetime="2023-01-10">10 January, 2023</time>
<h3 class="post__title"><a href="/2023/01/why-not-document-write/">Why Not document.write()?</a></h3>
</li>
<li class=list-ui__item>
<time class="post__date" datetime="2023-01-10">10 January, 2023</time>
<h3 class="post__title"><a href="/2023/01/foo/">Why Not document.write()?</a></h3>
</li>
<li class=list-ui__item>
<time class="post__date" datetime="2022-11-27">27 November, 2022</time>
<h3 class="post__title"><a href="/2022/11/async-or-defer/">async or defer</a></h3>
</li>
<li class=list-ui__item>
<time class="post__date" datetime="2022-11-11">11 November, 2022</time>
<h3 class="post__title"><a href="/2022/11/the-web-performance-lifecycle/">The Web Performance Lifecycle</a></h3>
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<li class=list-ui__item>
<time class="post__date" datetime="2022-10-12">12 October, 2022</time>
<h3 class="post__title"><a href="/2022/10/speeding-up-async-snippets/">Speeding Up Async Snippets</a></h3>
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<time class="post__date" datetime="2022-09-06">6 September, 2022</time>
<h3 class="post__title"><a href="/2022/09/critical-css-not-so-fast/">Critical CSS? Not So Fast!</a></h3>
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<li class=list-ui__item>
<time class="post__date" datetime="2022-09-05">5 September, 2022</time>
<h3 class="post__title"><a href="/2022/09/mommy-where-do-web-fonts-come-from/">Mommy, Where Do Web Fonts Come From?</a></h3>
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<li class=list-ui__item>
<time class="post__date" datetime="2022-08-24">24 August, 2022</time>
<h3 class="post__title"><a href="/2022/08/measure-what-you-impact-not-what-you-influence/">Measure What You Impact, Not What You Influence</a></h3>
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<p>Hi there, I’m <b>Harry Roberts</b>. I am an <b><a
href=https://web.archive.org/web/20190630140300/https://thenetawards.com/previous-winners/>award-winning</a>
Consultant Web Performance Engineer</b>, <b>designer</b>, <b>developer</b>,
<b>writer</b>, and <b>speaker</b> from the UK. I <b><a
href=https://csswizardry.com/archive/?ref=cta-sidebar-bio>write</a></b>, <b><a
href=https://twitter.com/csswizardry>Tweet</a></b>, <b><a
href=https://csswizardry.com/speaking/?ref=cta-sidebar-bio>speak</a></b>, and <b><a
href=http://github.com/csswizardry>share code</a></b> about measuring and
improving site-speed. You <a href=/services/?ref=cta-sidebar-bio>should hire me</a>.</p>
<p><a href=https://twitter.com/csswizardry class=twitter-follow-button data-show-count=true data-lang=en>Follow @csswizardry</a></p>
<p>You can now find me on <a rel="me" href="https://webperf.social/@csswizardry">Mastodon</a>.</p>
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<a href=/code-reviews/?ref=cta-sidebar#fix-it-fast class="btn btn--full btn--positive" data-sctrack=cta-sidebar elementtiming=cta-sidebar>Suffering? <b>Fix It Fast!</b>
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<h4>Projects</h4>
<ul class="[ list-ui list-ui--small ] mb">
<li><a href=https://github.com/inuitcss/inuitcss><img src=https://res.cloudinary.com/csswizardry/image/fetch/f_auto,q_auto/https://csswizardry.com/img/content/logo-inuitcss-home.png alt=inuitcss width=500 height=238 loading=lazy></a></li>
<li><a href=https://itcss.io/>ITCSS</a> – coming soon…</li>
<li><a href=https://cssguidelin.es/><img src=https://res.cloudinary.com/csswizardry/image/fetch/f_auto,q_auto/https://csswizardry.com/img/content/logo-css-guidelines-home.png alt="CSS Guidelines" width=540 height=180 loading=lazy></a></li>
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<h4>Next Appearance</h4>
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<li>
<h4 class="list-ui__title">Talk</h4>
<img src="/img/icons/pl.png" alt width="16" height="11" loading="lazy" /> <a href="https://infoshare.pl/">Infoshare</a>: Gdańsk (Poland), May 2023
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