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

Syntax

resource.redirectStart;

Return value

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

Example

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

function print_PerformanceEntries() {
  // Use getEntriesByType() to just get the "resource" events
  var p = performance.getEntriesByType("resource");
  for (var i=0; i < p.length; i++) {
    print_start_and_end_properties(p[i]);
  }
}
function print_start_and_end_properties(perfEntry) {
  // Print timestamps of the PerformanceEntry *start and *end properties
  properties = ["connectStart", "connectEnd",
                "domainLookupStart", "domainLookupEnd",
                "fetchStart",
                "redirectStart", "redirectEnd",
                "requestStart",
                "responseStart", "responseEnd",
                "secureConnectionStart"];

  for (var i=0; i < properties.length; i++) {
    // check each property
    var supported = properties[i] in perfEntry;
    if (supported) {
      var value = perfEntry[properties[i]];
      console.log("... " + properties[i] + " = " + value);
    } else {
      console.log("... " + properties[i] + " = NOT supported");
    }
  }
}

Specifications

Specification
Resource Timing Level 2 (Resource Timing 2)
# dom-performanceresourcetiming-redirectstart

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
redirectStart
43
12
40
No
30
11
43
43
42
30
11
4.0

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https://developer.mozilla.org/en-US/docs/Web/API/PerformanceResourceTiming/redirectStart