var req;
var elementId

function loadXMLDoc(url) {
	req = false;
    // branch for native XMLHttpRequest object
    if(window.XMLHttpRequest) {
    	try {
			req = new XMLHttpRequest();
        } catch(e) {
			req = false;
        }
    // branch for IE/Windows ActiveX version
    } else if(window.ActiveXObject) {
       	try {
        	req = new ActiveXObject("Msxml2.XMLHTTP");
      	} catch(e) {
        	try {
          		req = new ActiveXObject("Microsoft.XMLHTTP");
        	} catch(e) {
          		req = false;
        	}
		}
    }
}

function processReqChange() {
    // only if req shows "loaded"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            // ...processing statements go here...
			idElement=document.getElementById(elementId);
			idElement.innerHTML=req.responseText;
			//alert(req.responseText);
        } else {
            alert("There was a problem retrieving the XML data:\n" +
                req.statusText);
        }
    }
}

function selectModels(url){
	loadXMLDoc(url);
	if(req){
		req.onreadystatechange = processReqChange;
		elementId='model';
		req.open("GET", url, true);
		req.send("");
	}
	
}

function changeMake(url){
	i=document.newad.id_make.selectedIndex;
	id_make=document.newad.id_make.options[i].value;
	selectModels(url+"&id_make="+id_make);
}

function changeMake_search(url){
	i=document.search_form.id_make.selectedIndex;
	id_make=document.search_form.id_make.options[i].value;
	selectModels(url+"&id_make="+id_make);
}

function change_bigimg(img_name){
	document.images['big_img'].src="images/ads/"+img_name+".jpg";
}