// declare a global  XMLHTTP Request object
var XmlHttpObj;

// create an instance of XMLHTTPRequest Object, varies with browser type, try for IE first then Mozilla
function CreateXmlHttpObj()
{
	// try creating for IE (note: we don't know the user's browser type here, just attempting IE first.)
	try
	{
		XmlHttpObj = new ActiveXObject("Msxml2.XMLHTTP");
	}
	catch(e)
	{
		try
		{
			XmlHttpObj = new ActiveXObject("Microsoft.XMLHTTP");
		}
		catch(oc)
		{
			XmlHttpObj = null;
		}
	}
	// if unable to create using IE specific code then try creating for Mozilla (FireFox)
	if(!XmlHttpObj && typeof XMLHttpRequest != "undefined")
	{
		XmlHttpObj = new XMLHttpRequest();
	}
}

// called from onChange or onClick event of the continent dropdown list
function statesListOnChange(burl)
{
    var statesList = document.getElementById("statesList");

    // get selected continent from dropdown list
    var selectedContinent = statesList.options[statesList.selectedIndex].value;

    // url of page that will send xml data back to client browser
    var requestUrl;

	// use the following line if using asp
    requestUrl = burl + "/go/system/mod/statearea/code/" + encodeURIComponent(selectedContinent);

	CreateXmlHttpObj();

	// verify XmlHttpObj variable was successfully initialized
	if(XmlHttpObj)
	{
        // assign the StateChangeHandler function ( defined below in this file)
        // to be called when the state of the XmlHttpObj changes
        // receiving data back from the server is one such change
		XmlHttpObj.onreadystatechange = StateChangeHandler;

		// define the iteraction with the server -- true for as asynchronous.
		XmlHttpObj.open("GET", requestUrl,  true);

		// send request to server, null arg  when using "GET"
		XmlHttpObj.send(null);

		$('areasBar').style.display='block';
		$('submitButton').style.display='block';
	}
}


// this function called when state of  XmlHttpObj changes
// we're interested in the state that indicates data has been
// received from the server
function StateChangeHandler()
{
	// state ==4 indicates receiving response data from server is completed
	if(XmlHttpObj.readyState == 4)
	{
		// To make sure valid response is received from the server, 200 means response received is OK
		if(XmlHttpObj.status == 200)
		{
			PopulateareasList(XmlHttpObj.responseXML.documentElement);
		}
		else
		{
			alert("problem retrieving data from the server, status code: "  + XmlHttpObj.status);
		}
	}
}

// populate the contents of the country dropdown list
function PopulateareasList(countryNode)
{
    var areasList = document.getElementById("areasList");
	// clear the country list
	for (var count = areasList.options.length-1; count >-1; count--)
	{
		areasList.options[count] = null;
	}

	var countryNodes = countryNode.getElementsByTagName('area');
	var idValue;
	var textValue;
	var optionItem;
	// populate the dropdown list with data from the xml doc
	for (var count = 0; count < countryNodes.length; count++)
	{
   		textValue = GetInnerText(countryNodes[count]);
		idValue = countryNodes[count].getAttribute("id");
		optionItem = new Option( textValue, idValue,  false, false);
		areasList.options[areasList.length] = optionItem;
	}
}

// returns the node text value
function GetInnerText (node)
{
	 return (node.textContent || node.innerText || node.text) ;
}