function resetModelDD(){
	var makeVar = document.getElementById("make");
	if (makeVar != null){
		makeVar.selectedIndex = 0;
	}
}
window.onload = resetModelDD;
var dropDownToUpdate=null;
function createRequestObject(){

	var req;
	
	if(window.XMLHttpRequest){
	//For Firefox, Safari, Opera
	req = new XMLHttpRequest();
	}
	else if(window.ActiveXObject){
	//For IE 5+
	req = new ActiveXObject("Microsoft.XMLHTTP");
	}
	else{
		//Error for an old browser
		alert('Your browser is not IE 5 or higher, or Firefox or Safari or Opera');
	}
	
	return req;
}


function handleResponse(response){

	if(response != null && response.readyState == 4 && response.status == 200){
		var respText=trimStr(response.responseText);
		
		if (dropDownToUpdate != null && respText != null)
		{
			dropDownToUpdate.innerHTML=respText;
			dropDownToUpdate = null;
		}
	}
}
function sendRequest(method, url){
	//Make the XMLHttpRequest Object
	var http = createRequestObject();	
	if((method == 'get' || method == 'GET') && http != null ){
	http.open(method,url,true);
	http.onreadystatechange = function(){handleResponse(http);};
	http.send(null);
	}
}

function updateDropDown(dropId)
{
	var qURL = null;
	if (dropId == 'modelToUpdate')
	{
		dropDownToUpdate = document.getElementById(dropId);
		
		var make = getMake();
		qURL = 'carcrash_enh.jsp?queryType=model&make=' + make;
	} else if (dropId == 'yearToUpdate')
	{
		dropDownToUpdate = document.getElementById(dropId);
		var make = getMake();
		var model = getModel();
		
		qURL = 'carcrash_enh.jsp?queryType=year&make=' + make + '&model=' + model;
	}
	
	sendRequest('GET',qURL);
}
function getMake()
{
		var form=document.carcrashP1;
		var index = form.Make.selectedIndex;
		var make = form.Make[index].value;
		
		return make;
}
function getModel()
{
		var form=document.carcrashP1;
		var index = form.Model.selectedIndex;
		var model = form.Model[index].value;
		
		return model;
}
function showModel()
{
	var form=document.carcrashP1;
	form.submit();
}

function showModel2()
{
	updateDropDown('modelToUpdate');
}

function showYear()
{
	updateDropDown('yearToUpdate');
}

function enableGo()
{
	if(form.Year.selectedIndex!=1)
		document.carcrashP1.GoButton.disabled = false;
	else
		alert("Please enter Year.");
}

function nextPage()
{
   var form=document.carcrashP1;
   form.hiddenMake.value = form.Make.value;
   form.hiddenModel.value = form.Model.value;
   form.hiddenYear.value = form.Year.value;
   if(form.Model.selectedIndex==0 || form.Make.selectedIndex==0 || form.Year.selectedIndex==0)
   {
	   alert("Please enter valid combination of Model, Make and Year.");
	   return;
   }
   form.method="post";
   form.action="carcrashP2.jsp";   
   form.submit();
}

function trimStr(str)
{
	return str.replace(/^\s\s*/, '').replace(/\s\s*$/, '');
}