N/search Module
Search.id
Property Description: Script ID for a saved search, starting with customsearch. If you do not set this property and then save the search, NetSuite generates a script ID for you. This is not the internal NetSuite ID for the saved search. See Search.searchId.
Type: number
Supported Script Types: All script types For more information, see SuiteScript 2.0 Script Types.
Module: N/search Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=Search.id

// Code Example 1

//Add additonal code

//...

function createSearch() {

    var mySalesOrderSearch = search.create({

        type: search.Type.SALES_ORDER,

        title: 'My SalesOrder Search',

        id: 'customsearch_my_so_search',

     });

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_455917297362.html