The HTTP Timing-Allow-Origin response header specifies origins that are allowed to see values of attributes retrieved via features of the Resource Timing API, which would otherwise be reported as zero due to cross-origin restrictions.Header type Response header
Timing-Allow-Origin: *
Timing-Allow-Origin: <origin>, …, <originN>* (wildcard)Any origin may see timing resources.
<origin>Specifies a URI that may see the timing resources. You can specify multiple origins, separated by commas.
To allow any resource to see timing resources:
Timing-Allow-Origin: *To allow https://developer.mozilla.org to see timing resources, you can specify:
Timing-Allow-Origin: https://developer.mozilla.orgServer-Timing headerVary header