How to ping in JavaScript or jQuery?

Question

I want to create a game-like ping in Javascript, just like the game Counter Strike for example. I\'m doing an AJAX call to the server (MySQL) and want to calculate the time that

Answer 1

You will not be able to calculate accurate latency on client side (not counting java, flash or websockets), you need the server to calculate it and return the value in a response. Getting anything other than 0ms for localhost should be enough evidence of this :P

The earliest time in connection state gets me 300ms for stackoverflow.com, while the real number is closer to 100ms.

var a = new XMLHttpRequest();

a.onreadystatechange = function () {

    if (a.readyState === a.HEADERS_RECEIVED) {
        a.abort();
        console.log(new Date - abc);
    }
};

var abc = new Date;

a.open("GET", "/");
a.send(null);

Waiting for the full response (a.DONE) took 949ms