main frame - didStartProvisionalLoadForFrame
main frame - didCommitLoadForFrame
+CONSOLE WARNING: Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check http://xhr.spec.whatwg.org/.
main frame - didFinishDocumentLoadForFrame
main frame - didHandleOnloadEventsForFrame
main frame - didFinishLoadForFrame