Hi,
You could wrap the docReady script in an if statement.
If the field(s) are null then set their presence to hidden, otherwise set their presence to visible.
if (customerSubform.customerName == null)
{
customerSubform.presence = "hidden";
}
else
{
customerSubform.presence = "visible";
}
This is Javascript and would work in the docReady. You would need to adapt the object references.
Hope that helps,
Niall