//globals 
var vanfirst = "vanmake"; //id of first SELECT 
var vansecond = "vanmodel"; //id of second SELECT 
// 
function vansendRequest(url,params,HttpMethod) { 
if(!HttpMethod) { //check if http method is defined, if not, set it to GET 
   HttpMethod="GET"; 
} 
// 
// initialize request object 
vanreq=null; 
if(window.XMLHttpRequest){ 
   vanreq=new XMLHttpRequest; //mozilla/safari 
} else if(window.ActiveXObject){ 
   vanreq=new ActiveXObject("Microsoft.XMLHTTP"); //internet explorer 
} 
// 
//define callback handler 
if(vanreq) { 
// 
   vanreq.onreadystatechange=vanonReadyState; 
   vanreq.open(HttpMethod,url,true); 
   vanreq.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
   vanreq.send(params); 
} 
} 
// 
function vanonReadyState() { 
// 
var vanob2=document.getElementById(vansecond);
var vanready=vanreq.readyState;
var vandata=null;
if(vanready==4){ //check ready state
   vandata=vanreq.responseText; //read response data
   vanob2.removeChild(vanob2.firstChild);
   var vanchildEl = document.createElement('option'); 
   vanob2.appendChild(vanchildEl); 
   vanchildEl.innerHTML = 'All Models'; 
   vanchildEl.value = ''; 
   var vanitems = vandata.split(',');
   var vanlength = vanitems.length;
   for(var j = 0; j < vanlength; j++) {
      var vanchildEl = document.createElement('option'); //create option
      var vanEl = document.getElementById(vansecond);
      vanEl.appendChild(vanchildEl); //then append it to the second dropdown list
      vanchildEl.value = vanitems[j];
      vanchildEl.innerHTML = vanitems[j];
   } 
} 
} 
// 
function vanclicked() { 
// 
var vanel = document.getElementById(vanfirst);
var vanob2=document.getElementById(vansecond);
var vanselected = vanel.selectedIndex;
// 
while(vanob2.hasChildNodes()) { //removes items from dropdown if some already exist 
   vanob2.removeChild(vanob2.firstChild); 
} 
if(vanselected!= 0) { //if they choose something other than the first select-->"Select topic first" 
   var vanchildEl = document.createElement('option'); 
   vanob2.appendChild(vanchildEl); 
   vanchildEl.innerHTML = 'Please wait...'; 
   vansendRequest('/scripts/fetchvan.asp?make='+vanel.options[vanselected].value);
} else { //otherwise add the Select Topic First option and disable it 
   var vanchildEl = document.createElement('option'); 
   vanob2.appendChild(vanchildEl); 
   vanchildEl.innerHTML = 'All Models'; 
} 
}