How long ago did I load a page?

Question

Is there a way to get how long ago a page was loaded using javascript, without having first recorded the time to a javascript variable on page load? I'm hoping to create a scriptlet (javascript bookmark) that I can run on any web page and have it output how much time has passed since the browser loaded the page.

All of the "time spent on a page" solutions I've found so far rely on recording the time when the page first loads, which requires either access to modify a site, or a browser plugin. Is there no document property that stores when the page was loaded (started, finished, etc.) which can be accessed in javascript?

Answer 1

You could use window.performance.timing.loadEventEnd:

> performance.timing.loadEventEnd
1424280020354

window.performance.timing provides timestamps for the following page load lifecycle events, in order:

• navigationStart
• unloadEventStart
• unloadEventEnd
• redirectStart
• redirectEnd
• fetchStart
• domainLookupStart
• domainLookupEnd
• connectStart
• connectEnd
• secureConnectionStart
• requestStart
• responseStart
• responseEnd
• domLoading
• domInteractive
• domContentLoadedEventStart
• domContentLoadedEventEnd
• domComplete
• loadEventStart
• loadEventEnd

Source: Navigation Timing API on MDN

The Navigation Timing API is currently supported by most modern browsers. Exceptions: Safari < 8 on OSX, Safari on iOS and Opera Mini. - caniuse.com.