var request;
var queryString;   //will hold the POSTed data

function updateCities() {
	var txtSt = document.getElementById("stateabbr");
	if(txtSt.selectedIndex == 0) {
		if(document.getElementById("cityDisplay")) {
			document.getElementById("cityDisplay").style.visibility = 'hidden';
		}
		return false;
	}
	sendData();
	clearZip();
}

function sendData() {
	setQueryString();
	var url = "http://tse.porschedealer.com/dealer/usLocator/Script/ajax1.php";
	httpRequest("POST",url,true);
}

//event handler for XMLHttpRequest
function handleCheck() {
	if(request.readyState == 4) {
		for(i = (document.getElementById('cityid').options.length - 1); i >= 0; i--) {
			document.getElementById('cityid').remove(i);
		}
		
		if(request.status == 200) {
			var cityListStr = request.responseText;

			var cityListArray = new Array();

			if(cityListStr != '') {
				cityListArray = cityListStr.split(':::::');
			}

			if(document.getElementById('cityid')) {
				var newOption = document.createElement("OPTION");
				newOption.text = 'View all';
				newOption.value = 'ALL';
				document.getElementById('cityid').options.add(newOption);

				for(i = 0; i < cityListArray.length; i++) {
					var newOption = document.createElement("OPTION");
					newOption.text = cityListArray[i];
					newOption.value = cityListArray[i];
					document.getElementById('cityid').options.add(newOption);
				}
			}
		} else {
			alert("A problem occurred with communicating between the XMLHttpRequest object and the server program.");
        }
    }//end outer if
}

/* Initialize a Request object that is already constructed */
function initReq(reqType, url, bool) {
	/* Specify the function that will handle the HTTP response */
	request.onreadystatechange = handleCheck;
	request.open(reqType, url, bool);
	request.setRequestHeader("Content-Type",
            "application/x-www-form-urlencoded; charset=UTF-8");
	request.send(queryString);
}

/* Wrapper function for constructing a Request object.
 Parameters:
  reqType: The HTTP request type such as GET or POST.
  url: The URL of the server program.
  asynch: Whether to send the request asynchronously or not. */
function httpRequest(reqType, url, asynch) {
	// Mozilla-based browsers
	if(window.XMLHttpRequest) {
		request = new XMLHttpRequest();
	} else if(window.ActiveXObject) {
		request=new ActiveXObject("Msxml2.XMLHTTP");
		if (!request) {
			request=new ActiveXObject("Microsoft.XMLHTTP");
        }
     }
    //the request could still be null if neither ActiveXObject
    //initializations succeeded
    if(request) {
		initReq(reqType,url,asynch);
    }  else {
		alert("Your browser does not permit the use of all of this application's features!");
	}
}

function setQueryString() {
	queryString = "";
	var frm = document.getElementById('stateform');
	var numberElements = frm.elements.length;
	for(var i = 0; i < numberElements; i++) {
		if(i < numberElements - 1) {
			queryString += frm.elements[i].name + "=" + encodeURIComponent(frm.elements[i].value) + "&";
		} else {
			queryString += frm.elements[i].name + "=" + encodeURIComponent(frm.elements[i].value);
		}
	}
	
	queryString += '&country=US';
}

function clearZip() {
	if(document.getElementById("zip"))
		document.getElementById("zip").value = "";
}

function clearPhrase() {
	if(document.getElementById("phrase"))
		document.getElementById("phrase").value = "";
}

function clearState() {
	if(document.getElementById('state')) {
		document.getElementById('state').selectedIndex = 0;
	}
	if(document.getElementById('cityid')) {
		document.getElementById('cityid').selectedIndex = 0;
	}
	return false;
}