Trigger client script Field Changed function upon edit of a sublist column

For you to trigger a Field Changed function on a field on the item sublist, first, you have to take note of the parameters of the function. As indicated from the Client Event Types article, the function can have 3 parameters.
On this sample snippet, an alert is shown when the Quanity field on the Item sublist is changed.
function FieldChanged(type, name)
{ 
   if ((type == 'item') && (name == 'quantity' ))
      {
         alert("column has changed");
      }
}