//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 genCat(){
	
	var year = document.getElementById("year").value;
	var make = document.getElementById("make").value;
	var model = document.getElementById("model").value;
	var submodel = document.getElementById("submodel").value;
	var engine = document.getElementById("engine").value;
	
	
	if (engine == 0){ 
		toCat = "<select name='categ' id='categ'><option value='0'>Select Category</option></select>";
	
		document.getElementById("cat_here").innerHTML="<span id='cat_here'>"+toCat+"</span>";
		
		document.getElementById("categ").value= 0;
		return;
  	}
		toCat = "<select name='categ' id='categ'><option value='0'>Select Category</option></select>";
	
		document.getElementById("cat_here").innerHTML="<span id='cat_here'>"+toCat+"</span>";
		
		document.getElementById("categ").value= 0;
	
	xmlHttpx=GetXmlHttpObject()
	if (xmlHttpx==null){
  		alert ("Your browser does not support AJAX! \nThis page may not work properly.");
  		return;
  	} 
	
	var url="gen_cat2.php";
	url=url+"?year="+year;
	url=url+"&make="+make;
	url=url+"&model="+model;
	url=url+"&submodel="+submodel;
	url=url+"&engine="+engine;
	//url=url+"&district="+district;
	url=url+"&sid="+Math.random();
	xmlHttpx.onreadystatechange=function() { 
		if (xmlHttpx.readyState==4){ 
			document.getElementById("cat_here").innerHTML=xmlHttpx.responseText;
		}
	};
	xmlHttpx.open("GET",url,true);
	xmlHttpx.send(null);
	
}