Download and upload speed not matching with speed in speedtest.net

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Ajax

jQuery

I m trying to find the download and upload speed of my connection. For that im uploading a payload to a another server and simultaneously downloading payload from the same server. This way i am able to get a download and upload speed.
The issue is that i am not being able to get values almost as that in www.speedtest.net. Here are my scripts for upload and download.

upload

var uploadhttp;
var url = "http://Server/abc/";
var params =PAYLOAD(arnd 100kb)

function handler() {//Call a function when the state changes.
    if(uploadhttp.readyState == 4 && uploadhttp.status == 200) {
        alert(uploadhttp.responseText);
    }
}
function postMethod() {
    try
    {
    getHTTPObject();
    if(!uploadhttp)
        alert("failed to create object");
    uploadhttp.open("POST", url, true);//,"jio","rancore");

    //Send the proper header infomation along with the request
    uploadhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");

    uploadhttp.onreadystatechange = handler;
    uploadhttp.send(params);

    }
    catch(e)
    {
       alert(e);
    }
}
//I am callin postMethod ever 100ms so that it could upload the payload to the server hence giving me my upload speed.
//Similarly the download script is
var xhr;
 xhr = new XMLHttpRequest();
 
var data;

function getDownload()
{
	try
	{	
		xhr.onreadystatechange=function()
		{
			if (xhr.readyState==4 && xhr.status==200)
			{
				//alert(xhr.responseText);
			}
		}		

		xhr.open("GET", "http://server/download/speedtest.php", true);
	 xhr.send();
	  data=xhr.responseText;
	  //alert(data);
	}
	catch(e)
	{	
		alert(e);
	}
}
//To download a payload i have included a php script which reads a 40MB file and returns payload as a responseText

header('Access-Control-Allow-Origin: *');
  $filepath="/path/argo.MP4";
  $filesize =  filesize($filepath);
   $val=readfile($filepath);


    header('Cache-Control: no-cache');
    header('Content-Transfer-Encoding: binary');
    header('Content-Length: '. $filesize);

        echo $val;
  }
?>