The IHTMLPerformanceTiming::domainLookupStart property must return the time immediately before the user agent starts the domain name lookup for the current document. If a persistent connection is used or the current document is retrieved from relevant application caches or local resources, this attribute must return the same value as IHTMLPerformanceTiming::fetchStart.
HRESULT value = object.get_domainLookupStart(ULONGLONG* p);
An ULONGLONG value that represents the time immediately before the user agent starts the domain name lookup for the current document.
- Navigation Timing, Section 4.2
If a page is retrieved from an application cache, IHTMLPerformanceTiming::domainLookupStart has the same value as IHTMLPerformanceTiming::fetchStart.
The value reported by the IHTMLPerformanceTiming::domainLookupStart property represents the number of milliseconds between the recorded time and midnight January 1, 1970 (UTC).
Windows Internet Explorer 9. This property is supported only for documents displayed in IE9 Standards mode. For more information, see Defining Document Compatibility.