N/currentRecord Module
CurrentRecord.getCurrentSublistIndex()
Method Description: Returns the line number of the currently selected line.
Returns: number
Supported Script Types: Client scripts For more information, see SuiteScript 2.0 Client Script Type.
Governance: None
Module: N/currentRecord Module
Since: 2016.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=CurrentRecord.getCurrentSublistIndex(options)

// Code Example 1

//Add additional code

//...

var currIndex = objRecord.getCurrentSublistIndex({

    sublistId: 'item'

});

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4637585731.html