How to determine latency of a remote server through the browser

Question

I run a couple of game tunnelling servers and would like to have a page where the client can run a ping on all the servers and find out which is the most responsive. As far

Answer 1

Before the call to the server, record the Javascript time:

var startTime = new Date();

Load an image from the server:

var img = new Image()
img.onload = function() {
    // record end time
}
img.src = "http://server1.domain.com/ping.jpg";

As soon as the request is finished, record the time again. (Given of course that the request didn't time out.)

var endTime = new Date();

Your ping in milliseconds is:

var ping = endTime. getTime() - startTime.getTime();