Simple use of Network and Resource Timing APIs in JavaScript

NetworkResourceTimingApis.js

//Collects performance metrics for HTML documents.
performance.getEntries();
performance.getEntriesByType("navigation")[0];
performance.getEntriesByType("navigation")[0].serverTiming[0];

//Collects performance metrics for document-dependent resources.
//Stuff like style sheets, scripts, images, et cetera.
performance.getEntriesByType("resource")[0];
performance.getEntriesByType("resource")[0].serverTiming[0];
performance.getEntriesByType("resource")[1];
performance.getEntriesByType("resource")[1].serverTiming[1];
//Indexing continues until the last resource

//serverTiming only works if server is setting header values on requests.

//https://developers.google.com/web/fundamentals/performance/navigation-and-resource-timing
//https://developer.mozilla.org/en-US/docs/Web/API/Performance/getEntries