// copyright 2007, 2009 Michael J. Roberts

var xmlRequests = [];

function xmlSend(url, statusSpanID, cbFunc, content)
{
    var req;
    var tracker;

    if (statusSpanID)
        document.getElementById(statusSpanID).innerHTML = "";
    
    if (window.XMLHttpRequest)
        req = new XMLHttpRequest();
    else if (window.ActiveXObject)
        req = new ActiveXObject("Microsoft.XMLHTTP");
    if (req)
    {
        tracker = new Object();
        tracker.request = req;
        tracker.statusSpanID = statusSpanID;
        tracker.cbFunc = cbFunc;
        xmlRequests.push(tracker);
        req.onreadystatechange = xmlReqEvent;
        if (content == null) {
            req.open("GET", url + "&xml", true);
            req.send(content);
        } else {
            req.open("POST", url, true);
            req.setRequestHeader("Content-Type",
                                 "application/x-www-form-urlencoded");
            req.send(content + "&xml=1");
        }
    }
    else
    {
        window.open(
            url, "IFDBRequest",
            'width=400,height=400,left=10,top=10,scrollbars=1,resizable=1');
    }
}

function xmlReqEvent()
{
    var i;
    
    for (i = 0 ; i < xmlRequests.length ; ++i)
    {
        var tracker = xmlRequests[i];
        var req = tracker.request;

        if (req.readyState == 4)
        {
            xmlRequests.splice(i, 1);
            var msgspan = (tracker.statusSpanID
                           ? document.getElementById(tracker.statusSpanID)
                           : null);
            var resp = req.responseXML.documentElement;
            if (req.status == 200 && resp != null)
            {
                if (msgspan)
                    msgspan.innerHTML =
                        resp.getElementsByTagName('label')[0].firstChild.data;
                
                var errmsg = resp.getElementsByTagName('error');
                if (errmsg && errmsg[0] && errmsg[0].firstChild)
                    alert(errmsg[0].firstChild.data);
            }
            else
            {
                if (msgspan)
                    msgspan.innerHTML = "Not Saved";
                alert("An error occurred sending the update to the server. "
                      + "Please try again later.");
            }
            if (tracker.cbFunc)
                tracker.cbFunc(req.responseXML.documentElement);
        }
    }
}

function xmlChildText(parent, name)
{
    var child = parent.getElementsByTagName(name);
    return (child && child.length && child[0].firstChild
            ? child[0].firstChild.data
            : null);
}