function fCheckForm() {

    var sErr = "";

    if (document.fBookOnline.sRegNo.value=="") {
        sErr += "\n - Vehicle reg";
    }
    if (document.fBookOnline.sName.value=="") {
        sErr += "\n - Name";
    }
    if (document.fBookOnline.sTel.value=="") {
        sErr += "\n - Tel";
    }
    if (document.fBookOnline.sEmail.value=="") {
        sErr += "\n - Email";
    }
    if (document.fBookOnline.sDateTime.value=="") {
        sErr += "\n - Preferred date/time";
    }
    if (document.fBookOnline.sDetails.value=="") {
        sErr += "\n - Please provide details of how we can help";
    }
    if (document.fBookOnline.bTerms.checked==false) {
        sErr += "\n - Please tick the box to agree to our terms & conditions";
    }

    if (sErr!="") {
        alert("Please check the following:-\n" + sErr);
    } else {
        document.fBookOnline.action="pages/general/book-online_exec.php";
        document.fBookOnline.submit();
    }
}