PerformanceResourceTiming.responseStart

The responseStart read-only property returns a timestamp immediately after the browser receives the first byte of the response from the server, cache, or local resource.

Note: This feature is available in Web Workers.

Syntax

resource.responseStart;

Return value

A DOMHighResTimeStamp immediately after the browser receives the first byte of the response from the server.

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 Status Comment
Resource Timing Level 1
The definition of 'responseStart' in that specification.
Candidate Recommendation Initial definition.

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
responseStartChrome Full support 43Edge Full support 12Firefox Full support 40IE No support NoOpera Full support 30Safari Full support 11WebView Android Full support 43Chrome Android Full support 43Firefox Android Full support 42Opera Android Full support 30Safari iOS Full support 11Samsung Internet Android Full support 4.0

Legend

Full support
Full support
No support
No support