//Ajax functions
//w3schools.com
function GetXmlHttpObject(){
	var xmlHttp=null;
  	try{
		// Firefox, Opera 8.0+, Safari
		xmlHttp=new XMLHttpRequest();
	}
  	catch (e){
    // Internet Explorer
		try{
		  xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		}
    	catch (e){
		  xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
		}
    }
  	
	return xmlHttp;
} 

function genModel(){
	
	var year = document.getElementById("year").value;
	var make = document.getElementById("make").value;
	var sc1 = document.getElementById("sc1").value;
	var sc2 = document.getElementById("sc2").value;
	var sc3 = document.getElementById("sc3").value;
	var sc4 = document.getElementById("sc4").value;
	//var district = document.getElementById("district").value;
	
	//alert(district);
	if (make == 0){ 
		toModel = "<select name='model' id='model'><option value='0'>Select Model</option></select>";
		toSubModel = "<select name='submodel' id='submodel'><option value='0'>Select Sub Model</option></select>";
		toEngine = "<select name='engine' id='engine'><option value='0'>Select Engine</option></select>";
		//toCat = "<select name='categ' id='categ'><option value='0'>Select Category</option></select>";
		
  		document.getElementById("model_here").innerHTML="<span id='model_here'>"+toModel+"</span>";
		document.getElementById("sub_here").innerHTML="<span id='sub_here'>"+toSubModel+"</span>";
		document.getElementById("engine_here").innerHTML="<span id='engine_here'>"+toEngine+"</span>";
		//document.getElementById("cat_here").innerHTML="<span id='cat_here'>"+toCat+"</span>";
		
		document.getElementById("model").value= 0;
		document.getElementById("submodel").value= 0;
		document.getElementById("engine").value= 0;
		document.getElementById("categ").value= 0;
		return;
  	}
	
		toModel = "<select name='model' id='model'><option value='0'>Select Model</option></select>";
		toSubModel = "<select name='submodel' id='submodel'><option value='0'>Select Sub Model</option></select>";
		toEngine = "<select name='engine' id='engine'><option value='0'>Select Engine</option></select>";
		//toCat = "<select name='categ' id='categ'><option value='0'>Select Category</option></select>";
		
  		document.getElementById("model_here").innerHTML="<span id='model_here'>"+toModel+"</span>";
		document.getElementById("sub_here").innerHTML="<span id='sub_here'>"+toSubModel+"</span>";
		document.getElementById("engine_here").innerHTML="<span id='engine_here'>"+toEngine+"</span>";
		//document.getElementById("cat_here").innerHTML="<span id='cat_here'>"+toCat+"</span>";
		
		document.getElementById("model").value= 0;
		document.getElementById("submodel").value= 0;
		document.getElementById("engine").value= 0;
		document.getElementById("categ").value= 0;
	
	xmlHttpx1=GetXmlHttpObject()
	if (xmlHttpx1==null){
  		alert ("Your browser does not support AJAX! \nThis page may not work properly.");
  		return;
  	} 
	
	var url="gen_model_cat.php";
	url=url+"?year="+year;
	url=url+"&make="+make;
	url=url+"&sc1="+sc1;
	url=url+"&sc2="+sc2;
	url=url+"&sc3="+sc3;
	url=url+"&sc4="+sc4;
	//url=url+"&district="+district;
	url=url+"&sid="+Math.random();
	xmlHttpx1.onreadystatechange=function() { 
		if (xmlHttpx1.readyState==4){ 
			document.getElementById("model_here").innerHTML=xmlHttpx1.responseText;
		}
	};
	xmlHttpx1.open("GET",url,true);
	xmlHttpx1.send(null);
	
}