From a high level, user interfaces for web applications and traditional desktop applications share a common goal: respond to the user’s input as fast as possible. When it comes to responding to a user’s request to load a web site, the browser itself handles much of the responsiveness burden. It opens network connections to the requested site, parses the HTML, requests the associated resources, and so forth. Based on a careful analysis of this process, we can optimize our pages to render as fast as possible, but the browser is ultimately in control of loading and realizing the page.
As shown ...