function mailValidation(){
	var naam=document.getElementById('naam').value;
	if(naam==''){
		alert("Please enter naam.");
		document.getElementById('naam').focus();
		return false;
	}
	var telefoon=document.getElementById('telefoon').value;
	if(telefoon==''){
		alert("Please enter telefoon.");
		document.getElementById('telefoon').focus();
		return false;
	}
	var email=document.getElementById('email').value;
	if(email==''){
		alert("Please enter email.");
		document.getElementById('email').focus();
		return false;
	}
	var emailRegEx = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if(!email.match(emailRegEx)){
		alert("Please enter valid email address");	
		document.getElementById('email').focus();
		return false;	
	}
	var vraag_bericht=document.getElementById('vraag_bericht').value;
	if(vraag_bericht==''){
		alert("Please enter Vraag of Bericht.");
		document.getElementById('vraag_bericht').focus();
		return false;
	}
}

function contactValidation(){
	var naam=document.getElementById('naam').value;
	if(naam==''){
		alert("Please enter naam.");
		document.getElementById('naam').focus();
		return false;
	}
	var email=document.getElementById('email').value;
	if(email==''){
		alert("Please enter email.");
		document.getElementById('email').focus();
		return false;
	}
	var emailRegEx = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
	if(!email.match(emailRegEx)){
		alert("Please enter valid email address");	
		document.getElementById('email').focus();
		return false;	
	}
}