Preface

Despite working on the web every day, few developers have a good word to say about the monster they’ve created. Achingly slow sites with annoying overlays, cookie agreements, instant notifications, and obtrusive ads litter the web landscape.

While there may be some excuses for complex web applications, there’s little justification for sluggish content-based and ecommerce sites. People are notoriously impatient, and an unresponsive site receives fewer visitors and conversions.

This book provides advice, tips, and best practice for improving website performance.

Who Should Read This Book?

The performance options described in the following chapters range from quick, five-minute configuration changes to major website overhauls. We primarily concentrate on front-end activities and server configurations to optimize the code delivered to a browser.

Some back-end tips are provided, but this is often specific to your application, framework, database, and usage patterns. Server-side performance can often be improved with additional or more powerful computing resources.

Ideally, everyone involved in a project would consider performance from the start. Somewhat understandably, that rarely occurs, because no one can appreciate the speed of a website or application before it’s been created. Many of the tips can therefore be applied after your project has been delivered.

Conventions Used

Code Samples

Code in this book is displayed using a fixed-width font, like so:

<h1>A Perfect Summer's Day</h1>
<p>It was a lovely day for a walk in the park.
The birds were singing and the kids were all back at school.</p>
			

Where existing code is required for context, rather than repeat all of it, ⋮ will be displayed:

function animate() {
    ⋮
new_variable = "Hello";
}

Some lines of code should be entered on one line, but we’ve had to wrap them because of page constraints. An ➥ indicates a line break that exists for formatting purposes only, and should be ignored:

URL.open("http://www.sitepoint.com/responsive-web-
➥design-real-user-testing/?responsive1");

You’ll notice that we’ve used certain layout styles throughout this book to signify different types of information. Look out for the following items.

Tips, Notes, and Warnings

Supplementary Materials

• https://www.sitepoint.com/community/ are SitePoint’s forums, for help on any tricky problems.
• [email protected] is our email address, should you need to contact us to report a problem, or for any other reason.