Use the Shipping Item List as a Select Option in a Suitelet

1. Create a custom record type
   
   • Navigate to Customization > Lists, Records, & Fields > Record Types > New
   • Set the name – Shipping List
   • Set the ID – _rec_ship_list
   • Access type = no Permission Required
   • Save
2. Add a custom field that will source the Shipping Item List
   
   • Edit the Record created from Part A.
   • Click on new field
   • Set the name – shipping item list
   • Set the ID – _shipping_list  
   • Type = List/Record
   • List/Record = Shipping Method
   • Save
3. Create a new Record (Shipping List)
   
   • Open the custom record (Shipping List)
   • Click on View Records
   • Click on new
   • Set a Name to the record and Save
   • Take note of the Internal Id for this new record.

function demoSimpleForm(request, response) {
    if (request.getMethod() == 'GET') {
        var form = nlapiCreateForm('Simple Form');
        var cusRec = nlapiLoadRecord('customrecord_rec_ship_list', 1);
        var shipFld = cusRec.getField('custrecord_shipping_list');
        var options = shipFld.getSelectOptions();
        var select = form.addField('custpage_selectfield', 'select', 'My Custom shipping item');
        select.addSelectOption('', '');
        for (var i = 0; i < options.length; i++) {
            select.addSelectOption(options[i].id, options[i].text);
        }
        form.addSubmitButton('Submit');
        response.writePage(form);
    } else {
        dumpResponse(request, response);
    }
}