function validateFormOnSubmit1(theForm) {
var reason = "";

  reason += validateEmpty(theForm.commodity);
  reason += validateEmpty(theForm.quantity);
      
  if (reason != "") {
    alert("Some fields need correction:\n" + reason);
    return false;
  }

  return true;
}

function validateFormOnSubmit2(theForm) {
var reason = "";

  reason += validateEmpty(theForm.origin);
  reason += validateEmpty(theForm['pos[]']);
      
  if (reason != "") {
    alert("Some fields need correction:\n" + reason);
    return false;
  }

  return true;
}

function validateFormOnSubmit3(theForm) {
var reason1 = "";
var reason2 = "";

  reason1 += validateEmpty(theForm.tr_trucks);
  reason2 += validateEmpty(theForm.truck);
  
  if (reason1 != "" && reason2 != "") {
    alert("Some fields need correction:\n" + reason1 + reason2);
    return false;
  }

  return true;
}



function validateEmpty(fld) {
    var error = "";
  
    if (fld.value.length == 0) {
        fld.style.background = 'Yellow'; 
        error = "The required field "+fld.name+" has not been filled in.\n"
    } else {
        fld.style.background = 'White';
    }
    return error;   
}