Currently I'm working on Angular application that let's user measure loading time of specific page. I'm loading that page from my app as an iframe in the background and want to measure specific timestamps of loading that iframe using javascript performance API. PerformanceResourceTiming interface is ideal for me because I can get specific times like DNS or TCP connection time (described here: https://developer.mozilla.org/en-US/docs/Web/Performance/Navigation_and_resource_timings). My problem is, that when I get my PerformanceResourceTiming object, most of the properties return values of 0 (although in DevTools -> Network they're not equal to 0). What am I doing wrong? Thank you in advance for your help.