function isMail(strng)
			{	
				var x = strng;
				var filter  = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
				if (filter.test(x)) return true;
				else return false;
			}

		function CheckEmail() 
			{ 
				var email	= document.getElementById('email').value;	

				if(isMail(email)) return true;
				
				alert('Dit is geen geldig email adres. Controleer en probeer opnieuw!');
				return false;
			}