N/ui/serverWidget Module
Form.insertField()
Method Description: Inserts a field in front of another field.
Returns: void
Supported Script Types: SuiteScript 2.0 Suitelet Script Type and SuiteScript 2.0 User Event Script Type (beforeLoad(scriptContext))
Governance: None
Module: N/ui/serverWidget Module
Since: 2015.2
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=Form.insertField(options)

// Code Example 1

//Add additional code

//...

var form = serverWidget.createForm({

    title : 'Simple Form'

});

var field1 = form.addField({

    id : 'custpage_text',

    type : serverWidget.FieldType.TEXT,

    label : 'Text'

});

var field2 = form.addField({

    id : 'custpage_text2',

    type : serverWidget.FieldType.TEXT,

    label : 'Text'

});

form.insertField({

    field : field2,

    nextfield : 'textfield1'

});

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4339707334.html