This session looks at both page delivery and user interaction to highlight patterns and areas of improvement starting with proper benchmarking and profiling. Understanding what to improve (e.g. DOM manipulation) is as valuable as understanding what not to bother with (e.g. unrolling loops) We’ll also look at some of the new and shiny in HTML5 and ECMAScript5 and how certain features affect performance, e.g. data-* attributes, localStorage and various “shims”.