function checkPC(formname) {
var f = document.getElementById(formname);
	var pc = f.elements["postcode_nr"].value;
	if (pc.length == 4) {
		f.elements["postcode_lt"].focus();
		}
	}

var ajax_formhandler = function(url) {
	var handlerFunc = function(t) {
	var formarray = t.responseText.split('|');
	var fields = document.getElementsByTagName('input');
	for (i=0;i<fields.length-1;i++) {
		document.getElementById(fields[i].name).className = "validfield";
	}
	var textfields = document.getElementsByTagName('textarea');
	for (i=0;i<textfields.length;i++) {
		document.getElementById(textfields[i].name).className = "validfield";
		//alert(fields[i].name);
	}
	if (formarray[1] == 'error') {
		document.getElementById('errormessage').style.display = "block";
		for (i=2;i<formarray.length;i++) {
			document.getElementById(formarray[i]).className = "invalidfield";
		}
	} else {
		document.getElementById('errormessage').style.display = "none";
		document.getElementById(formarray[0]).innerHTML = formarray[2];
	}
}

var errFunc = function(t) {
    alert('Error ' + t.status + ' -- ' + t.statusText);
}

var formdata = Form.serialize( url );
new Ajax.Request('ajax_return.php?action='+url, {method:'post', postBody:formdata, onSuccess:handlerFunc, onFailure:errFunc});
}