Attempting to investigate page load error: what are "Scripting" and "Idle"?

Question

I have a site built on HTML / CSS / JS / PHP / MySQL, and I'm trying to determine what consumes most of the operations related to loading my pages. Google Chrome timeline shows

and I wonder what are "Scripting" and "Idle"? With that said, what is "Painting"?

Answer 1

Scenarios are defined by event scenarios in the documentation:

https://developers.google.com/web/tools/chrome-devtools/profile/evaluate-performance/performance-reference#scripting-events

Painting events are also described.

https://developers.google.com/web/tools/chrome-devtools/profile/evaluate-performance/performance-reference#painting-events

In standby mode, it seems like the time that was not spent processing any events.