function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			oldonload();
			func();
		}
	}
}

function focusLabels() {
if (!document.getElementsByTagName) return false;
var labels = document.getElementsByTagName("label");
for (var i=0; i<labels.length; i++) {
if (!labels[i].getAttribute("for")) continue;
labels[i].onclick = function() {
var id = this.getAttribute("for");
if (!document.getElementById(id)) return false;
var element = document.getElementById(id);
element.focus();
}
}
}


function validateForm(whichform) {
	for (var i=0; i<whichform.elements.length; i++) {
		var element = whichform.elements[i];
		if (element.className.indexOf("required") != -1) {
			if (!isFilled(element)) {
				alert("Vul a.u.b. het "+element.name+" veld in.");
				return false;
				}
			}
		if (element.className.indexOf("email") != -1) {
			if (!isEmail(element)) {
				alert("Het " +element.name+" veld moet een geldig emailadres bevatten.");
				return false;
				}
			}
		}
	return true;
	}


function prepareForms() {
	for (var i=0; i<document.forms.length; i++) {
		var thisform = document.forms[i];
		thisform.onsubmit = function() {
			return validateForm(this);
		}
	}
}

function isFilled(field) {
	if (field.value.length < 1 || field.value == field.defaultValue) {
		return false;
		} else {
			return true;
			}
		}
		
function isEmail(field) {
	if (field.value.indexOf("@") == -1 || field.value.indexOf(".") == -1){
		return false;
		} else {
			return true;
			}
	}

addLoadEvent(prepareForms);
addLoadEvent(focusLabels);