Navigating Timing Errata

This page will list known errata for Navigation Timing.

navigationStart attribute

Replace

If there is no previous document, this attribute must return the same value as fetchStart.

with

If there is no previous document, this attribute must return the time the current document is created.

5.1 Processing Model

The non-normative illustration should be:

And add the following paragraph before the illustration:

Note that user agents may choose to perform some of the steps involved in loading the document speculatively prior to user navigation e.g. the user agent could pre-resolve the host name, speculatively connect to the server hosting the document or prefetch the root document ahead of the actual user navigation. The timings in the PerformanceTiming interface represent the time spent waiting after user navigation in these steps. For example, in the case of speculative resolution that started and finished before user navigation and the user agent was able to use that result, the domainLookupStart and domainLookupEnd attributes should both return the same value as fetchStart. If the speculative resolution started before user navigation and finished after navigationStart and the user agent was able to use that result, the domainLookupStart attribute should return the same value as fetchStart and the domainLookupEnd attribute should return the time immediately after the name lookup is successfully done.