function checkForm(form){
	for(var i = 0; i < form.elements.length; i++){
		// document.write(form.elements[i].name.substring(0,2)+'<br />');
		if(form.elements[i].id.substring(0,2) == 'C_'){
			if(form.elements[i].className.substring(0,3) == 'var'){
				if(form.elements[i].value.replace(/^\s+|\s+$/g, '') == ''){
					alert(ucfirst(form.elements[i].name.substring(2).replace('_', '')) + ' is een verplicht veld');
					form.elements[i].className = form.elements[i].className + ' error';
					form.elements[i].focus();
				}				
			}
			if(form.elements[i].className.substring(0,3) == 'int'){
				if(isNaN(form.elements[i].value) || form.elements[i].value == ''){
					alert(form.elements[i].name + ' is niet een getal');
					form.elements[i].className = form.elements[i].className + ' error';
					form.elements[i].focus();
					return false;
				}
			}
		}
	}
}

function ucfirst( str ) { 
    str += '';
    var f = str.charAt(0).toUpperCase();
    return f + str.substr(1);
}