PerformanceResourceTiming: responseEnd property
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2017.
Note: This feature is available in Web Workers.
The responseEnd
read-only property returns a timestamp
immediately after the browser receives the last byte of the resource or immediately before the transport connection is closed, whichever comes first.
Unlike many other PerformanceResourceTiming
properties, the responseEnd
property is available for cross-origin requests without the need of the Timing-Allow-Origin
HTTP response header.
Value
A DOMHighResTimeStamp
immediately after the browser receives the last
byte of the resource or immediately before the transport connection is closed, whichever
comes first.
Examples
Measuring time to fetch (without redirects)
The responseEnd
and fetchStart
properties can be used to measure the overall time it took to fetch the final resource (without redirects). If you want to include redirects, the overall time to fetch is provided in the duration
property.
const timeToFetch = entry.responseEnd - entry.fetchStart;
Example using a PerformanceObserver
, which notifies of new resource
performance entries as they are recorded in the browser's performance timeline. Use the buffered
option to access entries from before the observer creation.
const observer = new PerformanceObserver((list) => {
list.getEntries().forEach((entry) => {
const timeToFetch = entry.responseEnd - entry.fetchStart;
if (timeToFetch > 0) {
console.log(`${entry.name}: Time to fetch: ${timeToFetch}ms`);
}
});
});
observer.observe({ type: "resource", buffered: true });
Example using Performance.getEntriesByType()
, which only shows resource
performance entries present in the browser's performance timeline at the time you call this method:
const resources = performance.getEntriesByType("resource");
resources.forEach((entry) => {
const timeToFetch = entry.responseEnd - entry.fetchStart;
if (timeToFetch > 0) {
console.log(`${entry.name}: Time to fetch: ${timeToFetch}ms`);
}
});
Specifications
Specification |
---|
Resource Timing # dom-performanceresourcetiming-responseend |
Browser compatibility
BCD tables only load in the browser