HTML5 AND JAVASCRIPT WEB APPS

I went to see the second part of this talk. I first went to see the talk of José Paumard, but that was not my cup of tea. After the break Wesley Hales showed off some of the features of HTML 5. Using his slidfast.js learning framework, he demoed websockets for live updates by having the audience connect to a voting page of which we could see the results come in on screen in realtime. Web storage allows you to keep a limited set of data on the client side. Syntactically, there are 3 equivalent ways to use this in Javascript, but in practice you have to be very careful about which syntax you use in which browser. It turns out one notation can be up to 3 times slower than the other in Firefox, but 3 times faster in Chrome. A less usefull feature for business purposes is adding events to changes of the orientation of the users device. He showed an example that would flip pages back and forth triggered by tilting the device. Geolocation and geofencing are used to limit content delivered to the browser to content relevant for the users location. And last, he used web workers to execute some multithreaded calculations.

The final part of the talk was about web page performance. He showed an overview of experiments by Google, Yahoo and Bing of how slower performance directly impacts page usage. The same experiment was used in tuesday's talk on "Faster Websites".
He introduced us to webpagetest.org. It's an online webpage analysis that shows how the page is loaded and runs some tests to see if you're using best practices for good performance. I think the Pagespeed Insights plugin for Chrome gives more info. Running webpagetest.org against www.thomsonreuters.com results in a score of 53/100 with room for improvement in compressing content, caching static content and use of CDN.
Using CDN would increase cache reuse for static files like jquery.js by not serving it yourself, but using a public server. He did note that using CDN could imply security risks, because you have no control over what version of a file resides in the users cache.
In the end this was an entertaining talk with some nice things to keep in the back of your head.