function confirmSubmit(oForm) {
			//loop through all elements of oForm Object              
			for (var i = 0; i < oForm.elements.length; i++) {
				var reClass = /notEmpty|required/;
				var classNames = oForm.elements[i].className;
				
				if (oForm.elements[i].type != "button" && oForm.elements[i].type != "submit") {
					oForm.elements[i].style.backgroundColor = 'white';
				}
				
				//check if className-string contains 'notEmpty'
				if (reClass.test(classNames)) {					
					if (oForm.elements[i].value == '' ) {
						var veldNaam = oForm.elements[i].name;
										
						alert("Het veld '" + veldNaam + "' is niet ingevuld.");
												
						oForm.elements[i].style.backgroundColor = 'pink';
						if (oForm.elements[i].disabled == false) oForm.elements[i].focus();
						
						return false;
					}
				}                        
			}
			
			if (oForm.elements['subject']) {
				if (oForm.elements['subject'].selectedIndex < 1 || oForm.elements['subject'].value == '') {
					alert('Er is nog geen onderwerp geselecteerd');
					return false;
				}
			}
			
			if (oForm.elements['mail']) {
				if (!isValidEmail(oForm.elements['mail'].value)) {
					alert('Er is geen correct mailadres ingevoerd');
					return false;
				}
			}
			return true;
		}
		 
		function isValidEmail(sText) {
			var reEmail = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
			return reEmail.test(sText);
		}
		
		function isValidDate(sDate) {
			//var reDate = /^(?:(\d){1,2}-){2}(\d{4})$/;
			var reDate = /^(?:0[1-9]|[12][0-9]|3[01])-(?:0[1-9]|1[0-2])-(?:19|20\d{2})$/;
			return reDate.test(sDate);
		}