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We've previously mentioned our plans to move to a more rapid release cycle for YUI, and now the work we put into automating our unit and functional testing in 3.6.0 is making that possible. YUI 3.7.0pr1 is now available to the developer community...

Pat Cavit ( @tivac ), a frontend engineer at ArenaNet and an active YUI contributor and community member, joined us at YUIConf 2011 to give this talk on automating build-time website optimizations such as file concatenation, minification, renaming,...

A couple of weeks ago, Yahoo! announced YSlow for Mobile at Velocity 2011 , bringing the power of YSlow performance analysis to the mobile world. YSlow for Mobile works as a bookmarklet , making it possible to run on browsers other than Firefox (as...

At the London Ajax meetup this week, Piotr (one of the creators of the rather good jsfiddle.net talked about spinners — the pretty common "I'm doing something" indicator — and how users perceive them. Apparently, people perceive Chrome to be faster...

YUI engineer Ryan Grove gave a talk recently at Yahoo! in which he laid out a vision for how to approach performance in YUI 3-based applications. The approach is philosophical, strategic, and practical — and it's the best summary I've seen so far of...

The April 2010 edition of the BayJax meetup at Yahoo! featured five speakers, all of whom are co-authors on the new High Performance JavaScript volume from O'Reilly ( free chapter available here ). There were about 200 attendees filling the URLs...

Gonzalo has posted details on the April 2010 BayJax meetup , which we'll be hosting at Yahoo! again next week: We are back with the first Bayjax meetup of the new year at Yahoo!. This month we are bringing you an extraordinary lineup of speakers on...

Nicholas C. Zakas has teamed with a select group of fellow Yahoo! engineers to produce a new volume from O'Reilly and Yahoo! Press on High Performance JavaScript . Nicholas's coauthors on the project include Julien Lecomte and Stoyan Stefanov of...

YUI architect Matt Sweeney's ( @msweeney ) talk at YUICONF 2009 focused on extracting maximum performance from YUI 3 . He drilled into the seed file options, lazy-loading strategies, and YUI 3 techniques for DOM and Event interaction that keep...

A few months ago Peter Higgins, a contributor to the Dojo Toolkit , adapted the SlickSpeed test framework to do higher level comparisons of how various JavaScript libraries perform when doing some "common" DHTML tasks. The new test framework is...

Douglas Crockford returns to YUI Theater with another chapter in his evolving lecture series. This session, "Ajax Performance," debunks common misconceptions about the relationship between JavaScript and performance and gives engineers a core focus...

This is part 5 in an ongoing series. You can read the other parts here: Image Optimization Part 1: The Importance of Images Image Optimization Part 2: Selecting the Right File Format Image Optimization Part 3: Four Steps to File Size Reduction Image...

This is part 4 in an ongoing series. You can read the other parts here: Image Optimization Part 1: The Importance of Images Image Optimization Part 2: Selecting the Right File Format Image Optimization Part 3: Four Steps to File Size Reduction In...

This is part 3 in an ongoing series. You can read the other parts here: Image Optimization Part 1: The Importance of Images Image Optimization Part 2: Selecting the Right File Format Image Optimization Part 4: Progressive JPEG…Hot or Not? This post...

This is part 2 in an ongoing series. You can read the other parts here: Image Optimization Part 1: The Importance of Images Image Optimization Part 3: Four Steps to File Size Reduction Image Optimization Part 4: Progressive JPEG…Hot or Not? This...

This is part 1 in an ongoing series. You can read the other parts here: Image Optimization Part 2: Selecting the Right File Format Image Optimization Part 3: Four Steps to File Size Reduction Image Optimization Part 4: Progressive JPEG…Hot or Not?...

When we set out to build an iPhone-optimized version of Yahoo! Search , we wanted to bring SearchMonkey , Search Assist, and other JavaScript-heavy Yahoo! Search features to the iPhone, but we also wanted the site to be blazing fast even over EDGE,...

In Performance Research Part 1 , we discussed how reducing the number of HTTP requests has the biggest impact on improving the response time and is often the easiest performance improvement to make. One technique without having to simplify the page...

At MacWorld 2008 , Steve Jobs announced that Apple sold 4 million iPhones to date, that's 20,000 iPhones sold every day. Net Applications reports that total web browsing on iPhone is up at 0.12% for December 2007, topping the web browsing on all...

Julien Lecomte , author of the YUI Compressor and the YUI Browser History Manager , recently gave a talk at Yahoo on the creation of high-performance DHTML applications. In this talk, Julien covers several major performance topics: Developing for...

Steve Souders is Yahoo's chief guru in the art and science of web performance and the author of the YSlow plugin for Firebug ; he is the author of High Performance Web Sites , a forthcoming title from O'Reilly (bonus points if you can guess which...

Joseph Smarr is the Chief Platform Architect at Plaxo, Inc., where he's led the engineering of Plaxo's address-book integration application. In the course of building Plaxo 3.0, which involved an ambitious foray into rich internet application...

Parallel Downloads The biggest impact on end-user response times is the number of components in the page. Each component requires an extra HTTP request, perhaps not when the cache is full, but definitely when the cache is empty. Knowing that the...

HTTP cookies are used for a variety of reasons such as authentication and personalization. Information about cookies is exchanged in the HTTP headers between web servers and browsers. This article discusses the impact of cookies on the overall user...

This is the second in a series of articles describing experiments conducted to learn more about optimizing web page performance. You may be wondering why you're reading a performance article on the YUI Blog. It turns out that most of web page...

It's no secret that users prefer faster web sites. I work in a dedicated team focused on quantifying and improving the performance of Yahoo! products worldwide. As part of our work, we conduct experiments related to web page performance. We are...