function vval(f) {
  var errstr = "";
  var Fields = new Array("name","company","email","tel","address1","town","postcode","country"); // order must be same as in form.
  var i=0;
  var j=0;
  var checkVAT = 0;
  // check compulsory
  for (i=0;i<f.elements.length;i++) {
    if (f.elements[i].name == Fields[j]) {
      if ((f.elements[i].value == "")||(f.elements[i].value == null)||(!f.elements[i].value)) {
        errstr += "\n- " + Fields[j];
      }
      j++;
    }
  }
  // check VATarea field
  for (i=0;i<f.elements.length;i++) {
    if (f.elements[i].name == "VATcode") {
      if (f.elements[i].checked == true) {
	checkVAT = 1;
      }
    }
  }
  if (checkVAT == 0) {
    errstr += "\n- please select a VATcode area.";
  }
  
  if (errstr != "") {
    errstr = "Sorry, the form cannot be submitted because\nthe following fields were empty:" + errstr;
    alert(errstr);
    return false;
  }else {
    return true;
  }
}