I am Working on Inventory adjustment record for their i am trying to add a line in "Adjustment" sublist so i am using client script here on current record i am adding a "Inventory Item" so netsuite throw me alert that "Need to configure inventory detail for line" and it does not allow to let me add Inventory item but it allow be to add non inventory item. I want to add Inventory item in sublist befpre saving on client script current record so is their any way to trigger it Please let me know if any or not.

Do you have stock with serial numbers? If so then youkd need to add the serial number as well as the item id.

SuiteScript 2.x Scripting Subrecords is where you want to start