Delay calculation in AJAX

Question

I want to show the connection speed (Latency?) Of the users of my website. I think this is possible by measuring the request of the XMLHttpRequest object and the response time. The code is as follows.

var t;
function ajsend(){
    var request = new XMLHttpRequest();
    var url;

    request.onreadystatechange = function(){
        if( request.readyState == 4 && request.status == 200 ){
            var u = new Date().valueOf();
            var timeTaken = u - t;
            var disp;
            if( timeTaken < 100 )
                disp = "Excellent! " + timeTaken + " milliseconds.";
            else if( timeTaken < 500 )
                disp = "Very Good! " + timeTaken + " milliseconds.";
            else if( timeTaken < 1200 )
                disp = "Normal! " + timeTaken + " milliseconds.";
            else if( timeTaken < 2000 )
                disp = "Poor! " + timeTaken + " milliseconds.";
            else
                disp = "Very Poor! " + timeTaken + " milliseconds.";
            document.getElementById("disp").innerHTML = disp;
        }
    };

    t = new Date().valueOf();
    url = "noscript.php";
    request.open("GET", url, true);
    request.send();
}

It works! But the result is slightly different from the Web Console browser dimension. So is this the best way from AJAX or any better way from AJAX? Thanks.

Answer 1

If you want to compare the time taken for the server to start responding, checking for readyState == 2might work better.

In ReadyState 2, the request received headers from the server, so it should be available a little earlier than readyState 4.

, JavaScript , - .