var xmlhttp;

function getModels(makeID) {
	xmlhttp = GetXmlHttpObject();
	
	if (xmlhttp == null) {
		alert ('Your browser does not support AJAX!');
		return;
	}
	
	var url = 'lib/ajax.php';
	url = url + '?a=models';
	url = url + '&q=' + makeID;
	url = url + '&sid=' + Math.random();
	xmlhttp.onreadystatechange = stateChangedModels;
	xmlhttp.open('GET', url, true);
	xmlhttp.send(null);
	
	document.getElementById('select_model').innerHTML = '<select class="vehicleboxlength" name="select_model" onchange="getYears(this.value)"><option value="0">Loading...</option></select>';
	document.getElementById('select_year').innerHTML = '<select class="vehicleboxlength" name="select_year"><option value="0">Loading...</option></select>';
}

function getYears(modelID) {
	xmlhttp = GetXmlHttpObject();
	
	if (xmlhttp == null) {
		alert ('Your browser does not support AJAX!');
		return;
	}
	
	var url = 'lib/ajax.php';
	url = url + '?a=years';
	url = url + '&q=' + modelID;
	url = url + '&sid=' + Math.random();
	xmlhttp.onreadystatechange = stateChangedYears;
	xmlhttp.open('GET', url, true);
	xmlhttp.send(null);
	
	document.getElementById('select_year').innerHTML = '<select class="vehicleboxlength" name="select_year"><option value="0">Loading...</option></select>';
}

function getPages(catID) {
	xmlhttp = GetXmlHttpObject();
	
	if (xmlhttp == null) {
		alert ('Your browser does not support AJAX!');
		return;
	}
	
	var url = '../lib/ajax.php';
	url = url + '?a=pages';
	url = url + '&q=' + catID;
	url = url + '&sid=' + Math.random();
	xmlhttp.onreadystatechange = stateChangedPages;
	xmlhttp.open('GET', url, true);
	xmlhttp.send(null);
}

function stateChangedModels() {
	if (xmlhttp.readyState == 4) {
		document.getElementById('select_model').innerHTML = xmlhttp.responseText;
		getYears(document.form_search.select_model.value);
	}
}

function stateChangedYears() {
	if (xmlhttp.readyState == 4) {
		document.getElementById('select_year').innerHTML = xmlhttp.responseText;
	}
}

function stateChangedPages() {
	if (xmlhttp.readyState == 4) {
		document.getElementById('select_page').innerHTML = xmlhttp.responseText;
	}
}

function GetXmlHttpObject() {
	if (window.XMLHttpRequest) {
		return new XMLHttpRequest();
	}
	
	if (window.ActiveXObject) {
		return new ActiveXObject('Microsoft.XMLHTTP');
	}
	
	return null;
}

function checkVehicleList() {
	if (document.form_search.select_year.value == '0') {
		alert('Please select a vehicle from the drop-down menus.');
		return false;
	}
	return true;
}

function setSelVal(value, selectId) {
	var i, si, v, args = setSelVal.arguments;
	if ((obj = document.getElementById(args[1])) != null) {
		v = args[0];
		for(i = 0; i < obj.length; i++) {
			if(obj.options[i].value == v) {
				si = i;
			}
		}
		obj.selectedIndex = si;
	}
}