PerformanceResourceTiming.redirectEnd

The redirectEnd read-only property returns a timestamp immediately after receiving the last byte of the response of the last redirect.

When fetching a resource, if there are multiple HTTP redirects, and any of the redirects have an origin that is different from the current document, and the timing allow check algorithm passes for each redirected resource, this property returns the time immediately after receiving the last byte of the response of the last redirect; otherwise, zero is returned.

To get the amount of redirects, see also PerformanceNavigationTiming.redirectCount.

Value

The redirectEnd property can have the following values:

  • A timestamp immediately after receiving the last byte of the response of the last redirect.
  • 0 if there is no redirect.
  • 0 if the resource is a cross-origin request and no Timing-Allow-Origin HTTP response header is used.

Examples

Measuring redirection time

The redirectEnd and redirectStart properties can be used to measure how long the redirection takes.

const redirect = entry.redirectEnd - entry.redirectStart;

Using a PerformanceObserver:

const observer = new PerformanceObserver((list) => {
  list.getEntries().forEach((entry) => {
    const redirect = entry.redirectEnd - entry.redirectStart;
    if (redirect > 0) {
      console.log(`${entry.name}: Redirect time: ${redirect}ms`);
    }
  });
});

observer.observe({ type: "resource", buffered: true });

Or 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 redirect = entry.redirectEnd - entry.redirectStart;
  if (redirect > 0) {
    console.log(`${entry.name}: Redirect time: ${redirect}ms`);
  }
});

Cross-origin timing information

If the value of the redirectEnd property is 0, the resource might be a cross-origin request. To allow seeing cross-origin timing information, the Timing-Allow-Origin HTTP response header needs to be set.

For example, to allow https://developer.mozilla.org to see timing resources, the cross-origin resource should send:

Timing-Allow-Origin: https://developer.mozilla.org

Specifications

Specification
Resource Timing
# dom-performanceresourcetiming-redirectend

Browser compatibility

BCD tables only load in the browser

See also