A tiny bit of math applied to the window.performance object in chrome and firefox.
<script src="/page/to/wp.js"></script>
navigationStart -> fetchStart : 124
fetchStart -> domainLookupStart : 0
domainLookupStart -> domainLookupEnd : 0
domainLookupEnd -> connectStart : 0
connectStart -> connectEnd : 0
connectEnd -> requestStart : 3
requestStart -> responseStart : 381
responseStart -> domLoading : 17
domLoading -> responseEnd : 751
responseEnd -> domInteractive : 22
domInteractive -> domContentLoadedEventStart : 0
domContentLoadedEventStart -> domContentLoadedEventEnd : 22
domContentLoadedEventEnd -> loadEventStart : 444
loadEventStart -> domComplete : 0
domComplete -> loadEventEnd : 3
.