PerformanceResourceTiming.domainLookupStart

The domainLookupStart read-only property returns the timestamp immediately before the browser starts the domain name lookup for the resource.

Note: This feature is available in Web Workers

Syntax

resource.domainLookupStart;

Return value

A DOMHighResTimeStamp immediately before the browser starts the domain name lookup for the resource.

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

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
domainLookupStart
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/domainLookupStart