Skip to Content
High Performance Web Sites
book

High Performance Web Sites

by Steve Souders
September 2007
Intermediate to advanced
170 pages
4h 24m
English
O'Reilly Media, Inc.
Content preview from High Performance Web Sites

Amazon

Figure 17-4. http://www.amazon.com

Amazon (http://www.amazon.com) is a relatively heavy page with a total page weight of 405K and 84 HTTP requests. Given the size and number of components in the page, the biggest performance improvement for Amazon would be to add a far future Expires header to their components (Rule 3). Only 3 out of 84 components have an Expires header. They use only one stylesheet and three scripts. The scripts are loaded one after the other, so it would be a simple improvement to combine them into a single HTTP request. The stylesheet and scripts should be gzipped. The three scripts are minified to a large degree, but further savings could be gained by removing all comments and extraneous carriage returns.

Even with the performance improvements identified by YSlow, the sheer number of images in the page (74) is a challenge. Nineteen of these images are used as backgrounds in CSS rules. Converting them into CSS sprites would reduce the total HTTP requests from 84 to 66.

Looking at the subset of HTTP requests shown in the waterfall chart in Figure 17-5, we see that because these images are all requested from the same hostname, only two images are downloaded in parallel, increasing the total page load time. Splitting this large number of images across two hostnames would double the amount of parallel downloads, significantly reducing the end user response time. ...

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

Even Faster Web Sites

Even Faster Web Sites

Steve Souders
Back-end Performance

Back-end Performance

Bruno Skvorc, Christopher Pitt, Tonino Jankov, Reza Lavaryan, Daniel Berman
Hacking Web Performance

Hacking Web Performance

Maximiliano Firtman

Publisher Resources

ISBN: 9780596529307Errata Page