var http_request = false;

function contactus()
{
    var yourname = document.getElementById("textfield").value;
    var youremail = document.getElementById("textfield2").value;// alert(youremail);
    var phone = document.getElementById("textfield3").value; //alert(friendemail);
    var message = document.getElementById("textarea").value; //alert (message);
    var environment = document.getElementById("environment").value; //alert (message);


    var poststr = "name=" + encodeURI(document.getElementById("textfield").value) +
                "&email=" + encodeURI(document.getElementById("textfield2").value) +
                "&phone=" + encodeURI(document.getElementById("textfield3").value) +
                "&environment=" + encodeURI(document.getElementById("environment").value) +
                "&msg=" + encodeURI(document.getElementById("textarea").value);

    makePOSTRequest('proc.php', poststr);
    alert("mail successfully sent.");
    window.open("contactus.html","_self");
}

function makePOSTRequest(url, parameters)
{
    http_request = false;
    if (window.XMLHttpRequest)
    { // Mozilla, Safari,...
        http_request = new XMLHttpRequest();
        if (http_request.overrideMimeType)
        {
            http_request.overrideMimeType('text/xml');
        }
    }
    else if (window.ActiveXObject)
    { // IE
        try
        {
            http_request = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch (e)
        {
            try
            {
                http_request = new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch (e) {}
        }
    }
    if (!http_request)
    {
        alert('Cannot create XMLHTTP instance');
        return false;
    }

    http_request.onreadystatechange = function()
    {
        if (http_request.readyState == 4)
        {
            if (http_request.status == 200)
            {
                result = http_request.responseText;
            }
            else
            {
                //alert('There was a problem with the request.');
            }
        }
    }
    http_request.open('POST',url, true);
    http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    http_request.setRequestHeader("Content-length", parameters.length);
    http_request.setRequestHeader("Connection", "close");
    http_request.send(parameters);
}