function sendAjaxRequest (filename, POST, returnFunction)
{
    var xmlHttpObject = false;

    if (typeof xmlHttpObject != 'undefined')
    {
        xmlHttpObject = new XMLHttpRequest();
    }
    if (!xmlHttpObject)
    {
        try
        {
            xmlHttpObject = new ActiveXObject("Msxml2.XMLHTTP");
        }
        catch(e)
        {
            try
            {
                xmlHttpObject = new ActiveXObject("Microsoft.XMLHTTP");
            }
            catch(e)
            {
                xmlHttpObject = null;
            }
        }
    }
    
    if (POST == null)
    {
        xmlHttpObject.open('GET', filename, true);
        xmlHttpObject.onreadystatechange = function() {returnResponse(returnFunction)};
        xmlHttpObject.send(null);
    }
    else
    {
        xmlHttpObject.open('POST', filename, true);
        xmlHttpObject.onreadystatechange = function() {returnResponse()};
        xmlHttpObject.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        xmlHttpObject.send(POST);    
    }
    
    function returnResponse ()
    {
        if (xmlHttpObject.readyState == 4)
        {
            if (returnFunction != null)
            {
                returnFunction(xmlHttpObject.responseText);
            }
        }
    }
    
}