Compares page load time between HTML5 Navigation timings and basic computation using Date.now() (examples/loadspeed.js). Requires PhantomJS 2.0

loadspeedv2.js

var page = require('webpage').create(),
    system = require('system'),
    t, address;

if (system.args.length === 1) {
    console.log('Usage: loadspeedv2.js <some URL>');
    phantom.exit(1);
} else {
    t = Date.now();
    address = system.args[1];
    page.open(address, function (status) {
        if (status !== 'success') {
            console.log('FAIL to load the address');
        } else {
            t = Date.now() - t;
			console.log('Loading time (PhantomJS) ' + t + ' msec');
			
			setTimeout(function() {
			//wait a few ms ...
			var timings = page.evaluate(function () {
                return window.performance.timing;
            });
			
			console.log('Loading time (Navigation Timing) ' + (timings.loadEventEnd-timings.navigationStart)  + ' msec');
			
			phantom.exit();
			}, 500);
        }      
    });
}

sample

//sample output


C:\phantomjs>phantomjs.exe loadspeedv2.js http://www.amazon.com/
Loading time (PhantomJS) 1862 msec
Loading time (Navigation Timing) 1861 msec