There are a lot of great talks this year. Here are a few I’ve earmarked:

• Full-stack Introspection Crash Course by Theo Schlossnagle
• An Open Source Project Called “Failure:” with Josh Berkus. Shane Warden, Ben Collins-Sussman, Brian Fitzpatrick, and Karl Fogel
• Barely Legal XXX Perl by Jos Boumans (entertaining speaker)
• Experience-driven Development: Designers and Developers Working in Harmony by Chris Shiflett and Jon Tan
• Do You Believe in the Users? by Ben Collins-Sussman and Brian Fitzpatrick
• CSS for High Performance JavaScript UI by Gavin Doughtie (this looks really good)
• Using Puppet: Real World Configuration Management by James Turnbull and Luke Kanies (this is at the same time as my talk, but if you’re more interested in ops Luke is doing great stuff)

If you’re going to OSCON please come by and say Hi.

The Combo Handler Service lets developers choose a customized subset of modules and have them served as a single HTTP request from Yahoo!’s worldwide CDN for faster delivery. Each module (file) is listed in the querystring. As an example, Eric shows that loading the YUI Rich Text Editor the old way would require downloading six separate scripts:

<script src=”http://yui.yahooapis.com/2.5.2/build/yahoo-dom-event/yahoo-dom-event.js”>
</script>
<script src=”http://yui.yahooapis.com/2.5.2/build/container/container_core-min.js”>
</script>
<script src=”http://yui.yahooapis.com/2.5.2/build/menu/menu-min.js”>
</script>
<script src=”http://yui.yahooapis.com/2.5.2/build/element/element-beta-min.js”">
</script>
<script src=”http://yui.yahooapis.com/2.5.2/build/button/button-min.js”>
</script>
<script src=”http://yui.yahooapis.com/2.5.2/build/editor/editor-beta-min.js”>
</script>

This is reduced to a single HTTP request by using the Combo Handler:

<script src=”http://yui.yahooapis.com/combo?2.5.2/build/yahoo-dom-event/yahoo-dom-event.js&
2.5.2/build/container/container_core-min.js&2.5.2/build/menu/menu-min.js&
2.5.2/build/element/element-beta-min.js&2.5.2/build/button/button-min.js&
2.5.2/build/editor/editor-beta-min.js”>
</script>

It’s important that developers using Combo Handler pay particular attention that they get the dependency order correct. I created the YUI Combo Handler: preserving order test page to show what happens if prerequisites are listed incorrectly. In this page instead of putting editor-beta-min.js as the last querystring parameter, I make it the first parameter. Not surprisingly, the page produces JavaScript errors. It would be great if Combo Handler ensured that the response had all the necessary prerequisites in the right order. With this enhancement the single request would be much simpler:

<script src=”http://yui.yahooapis.com/combo?2.5.2/build/editor/editor-beta-min.js”>
</script>

This is a great announcement. Web developers using YUI can now get a customized rollup hosted on Yahoo!’s CDN! This is the best of all worlds - reduced download size, fewer HTTP requests, and CDN hosting. I encourage other JavaScript frameworks to adopt YUI’s à la carte flexibility. Perhaps Google Ajax Libraries could then support features to serve up customized builds similar to what Combo Handler does. Well done.

I’m happy to see the number of woman awardees is increasing, with a real jump in the last two years. But I have two reservations. The percentage of woman winners is low, averaging only 5% over the last 30 years with a spike to 10% in the last two years. Also, most ACM award winners come from academia. I’m concerned that an analysis of similar award winners from industry would reveal even lower percentages for women. (more…)

The lineup of speakers was great. There was a lot of material packed in a 2-day conference. I stayed in the Performance track, but wanted to attend every session in the Operations track, too. Many speakers shared their slides, and there are videos and photos from some of the talks.

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• Test scripts can include taking actions based on DOM events, such as the creation of a DOM element or even the contents of a DOM element matching a specified pattern.
• An intuitive HTTP profile is displayed in the client app.
• Tests can be executed at five cites worldwide on the Keynote backbone.
• It’s free! You don’t need to be a Keynote customer to use it.

KITE 2.0 is available through an early adopters program. There are some features I’d like to see added: the ability to execute a test script multiple times, exporting test results measured from my client, and getting time measurements that correspond to certain events in the page. I recommend trying this early version if you’re looking for a tool to record and execute web page test scripts.

I recently hosted Andy Hopper (University of Cambridge) at Google to deliver his talk on Computing for the Future of the Planet (YouTube video). He covered a variety of areas that ranged from practical deployment issues that should be addressed today to futuristic concepts. The beginning of the talk, the part that was of most interest to me, was about energy efficient computing: adaptive datacentres and a “virtual battery” (moving computing tasks to where energy is available). Power consumption is certainly a key focus for Google and other large web companies. It’s intriguing to think about shifting data and processes in real time based on the cost of energy.

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<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.2.6/jquery.min.js">
</script>

The greatest benefit in my opinion is that any developer can leverage Google’s CDN to deliver the bulk of their JavaScript. From YSlow and my book I received a lot of feedback that Rule 2: Use a CDN was out of reach for many developers. I use jQuery in one of my personal projects and serve it on my hosted web site from one geographic location. Ouch. Being able to move that 21K closer to my users is great.

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The growing adoption of Ajax and DHTML means today’s web pages have more JavaScript than ever before. The average top ten U.S. web site[1] contains 252K of JavaScript. JavaScript slows pages down. When the browser starts downloading or executing JavaScript it won’t start any other parallel downloads. Also, anything below an external script is not rendered until the script is completely downloaded and executed. Even in the case where external scripts are cached the execution time can still slow down the user experience and thwart progressive rendering.

Every line of JavaScript code matters to a fast loading page. And yet, as shown in Table 1, the average top ten U.S. web site only executes 25% of the JavaScript functionality before the onload event.[2] Why track this relative to the onload event? Any code needed after the onload event (for dropdown menus, Ajax requests, etc.) could be downloaded later, making the initial page render more quickly.

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1. Split the initial payload
2. Load scripts without blocking
3. Don’t scatter scripts
4. Split dominant content domains
5. Make static content cookie-free
6. Reduce cookie weight
7. Minify CSS
8. Optimize images
9. Use iframes sparingly
10. To www or not to www

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At Web 2.0 Expo today I announce the release of Cuzillion. The tag line is ‘cuz there are zillion pages to check. It’s indispensable for people like me who are always pushing browsers to their limit trying to figure out how to squeeze out a little more performance.

I’m constantly thinking of or being asked about how browsers handle different sets of resources loaded in various ways. Before I would open an editor and build some test pages. Firing up a packet sniffer I would load these pages in different browsers to diagnose what was going on. I was starting my research on advanced techniques for loading scripts without blocking and realized the number of test pages needed to cover all the permutations was in the hundreds. That was the birth of Cuzillion. (more…)