The initiatorType read-only property is a string that represents the type of resource that initiated the performance event.

The value of this string is as follows:

  • If the initiator is a Element, the property returns the element's localName.
  • If the initiator is a CSS resource, the property returns "css".
  • If the initiator is a XMLHttpRequest object, the property returns "xmlhttprequest".
  • If the initiator is a PerformanceNavigationTiming object, the property returns an empty string ("").
Note: This feature is available in Web Workers.



Return value

A string representing the type of resource that initiated the performance event, as specified above.


function print_PerformanceEntries() {
  // Use getEntriesByType() to just get the "resource" events
  var p = performance.getEntriesByType("resource");
  for (var i=0; i < p.length; i++) {
function print_initiatorType(perfEntry) {
  // Print this performance entry object's initiatorType value
  var value = "initiatorType" in perfEntry;
  if (value)
    console.log("... initiatorType = " + perfEntry.initiatorType);
    console.log("... initiatorType = NOT supported");


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

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
initiatorTypeChrome 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


Full support  
Full support
No support  
No support