function CheckForm() {
    resetLabels();
    var ErrorCount = 0;           
    if (document.getElementById('txtNaam').value == '') {
        document.getElementById('lblErrorNaam').style.display = 'block';
        ErrorCount++;
    }
    if (document.getElementById('txtEmail').value == '') {
        document.getElementById('lblErrorEmail').style.display = 'block';
        ErrorCount++;
    } else if (!isEmail(document.getElementById('txtEmail').value)) {
        document.getElementById('lblErrorEmailOnjuist').style.display = 'block';
        ErrorCount++;   
    }  
    if (document.getElementById('txtLand').value == '') {
        document.getElementById('lblErrorLand').style.display = 'block';
        ErrorCount++;
    }
    
    var l_cbCategorie = document.getElementsByName("cbCategorie");
    var l_cbTaal = document.getElementsByName("rbTaal");
    var l_cbFonds = document.getElementsByName("rbFonds");
    var l_cbMailtype = document.getElementsByName("rbMailtype");
    
    var l_blnChecked = false;    
    for (var i = 0; i < l_cbCategorie.length; i++) {
        if (l_cbCategorie[i].checked) {
            l_blnChecked = true;
        }
    }
    if (!l_blnChecked) {
        document.getElementById('lblErrorCategorie').style.display = 'block';
        ErrorCount++;
    }
    
    l_blnChecked = false;    
    for (var i = 0; i < l_cbTaal.length; i++) {
        if (l_cbTaal[i].checked) {
            l_blnChecked = true;
        }
    }
    if (!l_blnChecked) {
        document.getElementById('lblErrorTaal').style.display = 'block';
        ErrorCount++;
    }
    
    l_blnChecked = false;    
    for (var i = 0; i < l_cbFonds.length; i++) {
        if (l_cbFonds[i].checked) {
            l_blnChecked = true;
        }
    }
    if (!l_blnChecked) {
        document.getElementById('lblErrorFonds').style.display = 'block';
        ErrorCount++;
    }
    
//    l_blnChecked = false;    
//    for (var i = 0; i < l_cbMailtype.length; i++) {
//        if (l_cbMailtype[i].checked) {
//            l_blnChecked = true;
//        }
//    }
//    if (!l_blnChecked) {
//        document.getElementById('lblErrorMailtype').style.display = 'block';
//        ErrorCount++;
//    }

    if (ErrorCount == 0) {
        return true;
    } else {
        return false;
    }
}

function resetLabels() {
    var x = document.getElementsByTagName('label');
    for (var i=0;i<x.length;i++) {
        x[i].style.display = 'none';
    }
}