function clearEmailField(theField) {
	var f = theField;
	var fieldtext = 'Uw emailadres'
	
	if (f.value == fieldtext) {
		f.value='';
	} else {
		if (f.value == '') {
		f.value = fieldtext;
		}
	}
}
function checkFormNewsletter(){
	document.getElementById('div_unvalid').style.display = 'none';
	var valid = true;
	if(document.getElementById('newsletter_voornaam').value == ''){
		valid = false;	
	}
/*	if(document.getElementById('newsletter_tussenvoegsel').value == ''){
		valid = false;	
	}
*/	
	if(document.getElementById('newsletter_achternaam').value == ''){
		valid = false;	
	}
	if(document.getElementById('newsletter_email').value == ''){
		valid = false;	
	}
	if(!valid){
		document.getElementById('div_unvalid').style.display = 'block';
	}else{
		var a = new ajaxNewsletter();
		a.setCallbackHandler(displayNewsletterResponseMessage);
		a.saveNewsletter({
			voornaam:document.getElementById('newsletter_voornaam').value,
			tussenvoegsel:document.getElementById('newsletter_tussenvoegsel').value,
			achternaam:document.getElementById('newsletter_achternaam').value,
			email:document.getElementById('newsletter_email').value
			});
	}
}
function displayNewsletterResponseMessage(msg){
	document.getElementById('content_nieuwsbrief').style.display = 'none';
	document.getElementById('div_thank_you').style.display = 'block';
}