How To Improve Web Sites Performance

The first time I saw Steve Souders was at HTML5 Conference 2013 in San Francisco. Just in case you haven't heard about him, here is a heads up: He is the Head Performance Engineer at Google, previously Chief Performance at Yahoo!, Creator of YSlow. More about him, please refer to:

He gave an astonishing speech of "How fast are we going now?" as an opening speaker and I was stunned by his knowledge and contribution to the web performance world. I bought his book

[High Performance Web Sites]

right after the conference and spend 2 days to finish reading it. I am so convinced by the 14 rules which are listed in his book. All those rules are backed by some concrete data and examples. Most of those rules are just like a best practice in my daily work but I never asked why we should follow those. Quite a few rules are some knowledge I haven't touched yet, like "Avoid Redirects". In this blog, I would like to share those rules with all the web performance savvy:

1) Make fewer HTTP Requests

Make fewer HTTP requests.

2) Use a Content Delivery Network

Use a content delivery network.

3) Add an Expires Header

Add a far future Expires header to your components.

4) Gzip Components

Gzip your scripts and stylesheets.

5) Put Style sheets at the Top

Put your stylesheets in the document HEAD using the LINK tag.

6) Put Scripts at the Bottom

Move scripts to the bottom of the page.

7) Avoid CSS Expressions

Avoid CSS expressions.

8) Make JavaScript and CSS External

Put your JavaScript and CSS in external files.

9) Reduce DNS Lookups

Reduce DNS lookups by using Keep-Alive and fewer domains.

10) Minify JavaScript

Minify your JavaScript source code.

11) Avoid Redirects

Find ways to avoid redirects.

12) Remove Duplicate Scripts

Make sure scripts are included only once.

13) Configure Etags

Reconfigure or remove ETags.

14) Make Ajax Cacheable

Make sure your Ajax requests follow the performance guidelines, especially having a far future Expires header.

I highly recommend this book if you would like to improve the performance of your website. For detailed explanation and examples of those rules, please see:

Yang Zhao

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