We are attempting to enter an Item value at the Sales Order Line level and determine if that value already exists as a key in a custom file.  If the value exists, we want to extract data from the custom file and populate portions of the Sales Order Line currently being created.  One of the fields we want to populate is the Line Item value, replacing the Item value we originally placed in the field.  I know js but am new to Netsuite and am having trouble recognizing when a value has been entered into the Sales Order Line Item