function radioRequired(src, image) {
	// checks if a radio button is selected
	image.style.visibility='visible';
	var itemchecked = false;
	for(var j = 0; j < src.length; j++) {
	if(src[j].checked) {
		itemchecked = true;
		break;
	}
	}
	if(itemchecked)
		image.src='/img/aan.gif';
	else
		image.src='/img/uit.gif';

	return itemchecked;

}

function normalRequired(src, image) {
	// checks if the input field is filled.
	var returnValue = false;
	image.style.visibility='visible';
	if(src.value) {
		image.src='/img/aan.gif';
		returnValue = true;
	} else {
		image.src='/img/uit.gif';
		returnValue = false;
	}
	return returnValue;
}

function emailRequired(src, image){
	// Checks if an email adress is filled in correctly
	image.style.visibility='visible';
	var emailreg = /^[a-zA-Z0-9._-]+@([a-zA-Z0-9.-]+\.)+[a-zA-Z0-9.-]{2,5}$/;
		if(emailreg.test(src.value)){
			image.src='/img/aan.gif';
			returnValue = true;
		} else {
			image.src='/img/uit.gif';
			returnValue = false;
		}
	return returnValue;
}