function getParameterByName(name, url) {
    if (!url) {
      url = window.location.href;
    }
    name = name.replace(/[[]]/g, "\$&");
    var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
        results = regex.exec(url);
    if (!results) return null;
    if (!results[2]) return '';
    return decodeURIComponent(results[2].replace(/+/g, " "));
}
function httpPostAsync(theUrl, paymentId, callbackPOST)
{
    var xmlHttp = new XMLHttpRequest();
    var params="paymentId="+paymentId+"&key="+key+"&amt="+resp[0].toPay;
    params += "&order_no="+resp[0].ord_no+"&firmId="+resp[0].firmId+"&storeNo="+resp[0].storeNo;
    xmlHttp.open("POST", theUrl, true);
    xmlHttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xmlHttp.onreadystatechange = function() {
        if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
        {
            callbackPOST(xmlHttp.responseText);
            return;
        }
        else {
            document.getElementById("paytext").innerHTML = "error in payment";
            document.getElementById("download").innerHTML="";
        }
    }
    xmlHttp.send(params);
}