Page building is the first phase of a client-side web application's lifecycle: the browser processes HTML to create the DOM, then runs global JavaScript as it encounters script nodes. That code can modify the DOM and register event handlers before the application enters event handling. section 2.4 section 2.1
A page that logs activity
A small interface adds a “Page loading” message during page building. It also registers mousemove and click handlers, which add messages when those events occur. section 2.1
Figure 2.1. The lifecycle of a client-side web application starts with the user specifying a website address (or clicking a link) and ends when the user leaves the web page. It’s composed of two steps: page building and event handling.
Shows how page building and event handling fit into the client-side application lifecycle. section 2.1
