After harvesting the performance low-hanging fruits suggested by YSlow and PageSpeed, what do you do next to improve the performance of your web application? You work on improving the user's perception of speed and time. We all know perceptions lie and perceptions of time and duration even more so. So how do you make users believe the application is fast and responsive? The word is "progressive". When the page components download in parallel and don't block each other, the page loads quicker. And when the page renders progressively, it not only gives the user confidence and assurance that the applications works fine and they'll soon complete their task but it also appears that the app is snappier and more responsive.
In this deep-dive talk you'll learn about topics such as:
the role of progressive (downloads, rendering, enhancement) in the front-end performance
avoiding downloads block from unexpected sources such as favicons and conditional comments
CSS and high-performance
tricks used by the big guys (Yahoo, Amazon, Google) to cheat their way to better speed perception