RAIL stands for four distinct aspects of web app life cycle:
- Response: process events in under 50ms
- Animation: produce a frame in 10 ms
- Idle: maximize idle time
- Load: deliver content and become interactive in under 5 seconds
Navigation Timing API
The Navigation Timing API provides data that can be used to measure the performance of a web site.
- The load event is fired when the whole page has loaded, including all dependent resources such as stylesheets and images.
- The DOMContentLoaded event fires when the initial HTML document has been completely loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading.
- First Meaningful Paint
- Time to Interactive