RAIL model

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.

window.performance.timing

• 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.

Metrics

• First Meaningful Paint
• Time to Interactive

See:

• Measure performance with the RAIL model
• Performance audits