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;
}