Question

What is the purpose of the property PerformanceTiming.fetchStart?

(a) Browser ready to fetch input

(b) Browser ready to fetch document

(c) Browser ready to fetch summary

(d) Browser ready to fetch output

I got this question during a job interview.

Enquiry is from Integrating the Performance Object with perfLogger in chapter Invocation and Performance Navigation of JavaScript

Answer 1

The correct choice is (b) Browser ready to fetch document

To explain I would say: The PerformanceTiming.fetchStart read-only property returns an unsigned long long representing the moment, in milliseconds since the UNIX epoch, the browser is ready to fetch the document using an HTTP request. If there is no previous document, this value will be the same as PerformanceTiming.fetchStart.