N/ui/serverWidget Module
Form.updateDefaultValues()
Method Description: Updates the default values of multiple fields on the form.
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: 2016.1
Search NetSuite - https://system.netsuite.com/app/help/helpcenter.nl?search=Form.updateDefaultValues(options)

// Code Example 1

//Add additional code

//...

var form = serverWidget.createForm({

    title : 'Simple Form'

});

var field = form.addField({

    id : 'custpage_text',

    type : serverWidget.FieldType.TEXT,

    label : 'Text'

});

form.updateDefaultValues({

    custpage_text : 'Text Goes Here'

})

//...

//Add additional code



//SOURCE: https://system.netsuite.com/app/help/helpcenter.nl?fid=section_4340360899.html