function use(id) {
	return(document.getElementById(id));
}

function updatePostcode() {
	var postcode = use('postcode').value;
	var nummer = use('postcode').value;
	
	ajax('includes/postcode.php?postcode=' + postcode + '&nummer=' + nummer, function(response) {
		var response = eval('(' + response + ')');

		var postcode = response[0];
		var adressen = response[1];
		
		if (postcode[3] == 'FOUND') {
			use('straatnaam').value = postcode[4];
			use('plaats').value = postcode[5];
			use('postcode').value = postcode[0] + ' ' + postcode[1];
		} else {
			use('straatnaam').value = '';
			use('plaats').value = '';
		}
	});
}

function ajax(url, callbackFunction)
{
	var request = window.XMLHttpRequest ?
		new XMLHttpRequest() : new ActiveXObject("MSXML2.XMLHTTP.3.0");
	request.open("GET", url, true);
	request.onreadystatechange = function()
	{
		if (request.readyState == 4 && request.status == 200)
		{
			if (request.responseText)
			{
				callbackFunction(request.responseText);
			}
		}
	};
	request.send(null);
}

function ajax_post(url, vars, callbackFunction)
{
	var request = window.XMLHttpRequest ?
		new XMLHttpRequest() : new ActiveXObject("MSXML2.XMLHTTP.3.0");
	request.open("POST", url, true);
	request.setRequestHeader("Content-Type",
						   "application/x-www-form-urlencoded"); 

	request.onreadystatechange = function() {
		if (request.readyState == 4 && request.status == 200) {
			if (request.responseText) {
				callbackFunction(request.responseText);
			}
		}
	};
	request.send(vars);
}