var req;
function ajax(){
	url = 'advancedSearch.php';

	url += '?merk=' + document.getElementById('merk').options[document.getElementById('merk').selectedIndex].value;
	url += '&pageType=' + document.getElementById('pageType').value;
	url += '&brandstof=' + document.getElementById('brandstof').options[document.getElementById('brandstof').selectedIndex].value;
	url += '&versnellingsbak=' + document.getElementById('versnellingsbak').options[document.getElementById('versnellingsbak').selectedIndex].value;

	url+= '&rand=' + (Math.round(Math.random()*10000)+1);
    // branch for native XMLHttpRequest object
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = processReqChange;
        req.open('GET', url, true);
        req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        req.send("");
    // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        req = new ActiveXObject('Microsoft.XMLHTTP')
        if (req) {
            req.onreadystatechange = processReqChange;
            req.open('GET', url, true);
            req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            req.send("");
        }
    }
}

function processReqChange() {
    // only if req shows 'loaded'
    if (req.readyState == 4) {
        // only if 'OK'
        if (req.status == 200) {
            document.getElementById('formAdvancedSearch').innerHTML = req.responseText;
        } else {
            alert('There was a problem retrieving the XML data: ' +
                req.responseText);
        }
    }
}

function showAdvancedSearch(){
	document.getElementById('advancedSearch').style.display='block';
	document.getElementById('downLink').style.display='none';
	document.getElementById('upLink').style.display='block';
}

function hideAdvancedSearch(){
	document.getElementById('advancedSearch').style.display='none';
	document.getElementById('upLink').style.display='none';
	document.getElementById('downLink').style.display='block';
}

function showSimpleSearch(){
	document.getElementById('simpleSearch').style.display='block';
}