// stores the reference to the XMLHttpRequest object
var xmlHttp = createXmlHttpRequestObject();
var ele = '';
// retrieves the XMLHttpRequest object
function createXmlHttpRequestObject()
{
    // will store the reference to the XMLHttpRequest object
    var xmlHttp;
    // if running Internet Explorer
    if(window.ActiveXObject)
    {
        try
        {
            xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
        }
        catch (e)
        {
            xmlHttp = false;
        }
    }
    // if running Mozilla or other browsers
    else
    {
        try
        {
            xmlHttp = new XMLHttpRequest();
        }
        catch (e)
        {
            xmlHttp = false;
        }
    }
    // return the created object or display an error message
    if (!xmlHttp)
    alert("Error creating the XMLHttpRequest object.");
    else
    return xmlHttp;
}


// make asynchronous HTTP request using the XMLHttpRequest object
function process(url,elementName)
{
    // proceed only if the xmlHttp object isn't busy
    if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0)
    {
        ele = elementName;
        // execute the quickstart.php page from the server
        xmlHttp.open("GET", url, true);
        // define the method to handle server responses
        xmlHttp.onreadystatechange = handleServerResponse;
        // make the server request
        xmlHttp.send(null);
    }
    else
    // if the connection is busy, try again after one second
    setTimeout('process(url,elementName)', 1000);
}

// executed automatically when a message is received from the server
function handleServerResponse()
{
    // move forward only if the transaction has completed
    if (xmlHttp.readyState == 4)
    {
        // status of 200 indicates the transaction completed successfully
        if (xmlHttp.status == 200)
        {
            // extract the XML retrieved from the server
            //xmlResponse = xmlHttp.responseText;
            helloMessage = xmlHttp.responseText;
            // obtain the document element (the root element) of the XML structure
            //xmlDocumentElement = xmlResponse.documentElement;
            // get the text message, which is in the first child of
            // the the document element
            //helloMessage = xmlDocumentElement.firstChild.data;
            // update the client display using the data received from the server
            document.getElementById(ele).innerHTML = '<i>' + helloMessage + '</i>';
            // restart sequence

        }
        // a HTTP status different than 200 signals an error
        else
        {
            alert("There was a problem accessing the server: " + xmlHttp.statusText);
        }
    }
}