内容简介

Performance is critical to the success of any web site, and yet today's web applications push browsers to their limits with increasing amounts of rich content and heavy use of Ajax. In this book, Steve Souders, web performance evangelist at Google and former Chief Performance Yahoo!, provides valuable techniques to help you optimize your site's performance. Souders' previous book, the bestselling High Performance Web Sites, shocked the web development world by revealing that 80% of the time it takes for a web page to load is on the client side. In Even Faster Web Sites, Souders and eight expert contributors provide best practices and pragmatic advice for improving your site's performance in three critical categories: *JavaScript-Get advice for understanding Ajax performance, writing efficient JavaScript, creating responsive applications, loading scripts without blocking other components, and more. *Network-Learn to share resources across multiple domains, reduce image size without loss of quality, and use chunked encoding to render pages faster. *Browser-Discover alternatives to iframes, how to simplify CSS selectors, and other techniques. Speed is essential for today's rich media web sites and Web 2.0 applications. With this book, you'll learn how to shave precious seconds off your sites' load times and make them respond even faster. This book contains six guest chapters contributed by Dion Almaer, Doug Crockford, Ben Galbraith, Tony Gentilcore, Dylan Schiemann, Stoyan Stefanov, Nicole Sullivan, and Nicholas C. Zakas.

作者简介

Steve Souders现在Google工作，负责Web性能和开源组织。他是Firebug的性能分析扩展YSlow的创建者，也是O’Reilly Web性能与运作会议Velocity的联合主席。Steve经常在技术会议和诸如Microsoft、Amazon、MySpace、

LinkedIn和Facebook这样的知名高科技公司发表演讲。

特约作者：

Dion Almaer, Douglas Crockford,

Ben Galbraith, Tony Gentilcore,

Dylan Schiemann, Stoyan

Stefanov, Nicole Sullivan, and

Nicholas C. Zakas

精彩摘录

TimersarethedefactostandardforsplittingupJavaScriptcodeexecutioninbrowsers.Wheneverascriptistakingtoolongtocomplete,looktodelaypartsoftheexecutionuntillater.Notethatverysmalltimerdelayscanalsocausethebrowsertobecomeunresponsive.It’srecommendedtoneveruseadelayofzeromilliseconds,asthisisn’tenoughtimeforallbrowserstoproperlyupdatetheirdisplay.Ingeneral,delaysbetween50and100millisecondsareappropriateandallowbrowsersenoughidletimetoperformnecessarydisplayupdates.

——引自第104页

bydefault,allfunctionspassedintosetTimeoutarerunintheglobalcontext,sothisisequaltowindow.

——引自第106页