PerformanceResourceTiming.redirectStart

The redirectStart read-only property returns a timestamp representing the start time of the fetch which that initiates the redirect.

If there are HTTP redirects when fetching the resource and if any of the redirects are not from the same origin as the current document, but the timing allow check algorithm passes for each redirected resource, this property returns the starting time of the fetch that initiates the redirect; otherwise, zero is returned.

Note: This feature is available in Web Workers

Value

A timestamp representing the start time of the fetch which initiates the redirect.

Examples

In the following example, the value of the *Start and *End properties of all "resource" type events are logged.

function printPerformanceEntries() {
  // Use getEntriesByType() to just get the "resource" events
  performance.getEntriesByType("resource")
    .forEach((entry) => {
      printStartAndEndProperties(entry);
    });
}

function printStartAndEndProperties(perfEntry) {
  // Print timestamps of the *start and *end properties
  properties = ["connectStart", "connectEnd",
                "domainLookupStart", "domainLookupEnd",
                "fetchStart",
                "redirectStart", "redirectEnd",
                "requestStart",
                "responseStart", "responseEnd",
                "secureConnectionStart"];

  for (const property of properties) {
    // Log the property
    console.log(`${property} = ${perfEntry[property] ?? "NOT supported"}`);
  }
}

Specifications

Specification
Resource Timing Level 2
# dom-performanceresourcetiming-redirectstart

Browser compatibility

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