How to keep value in textarea field in suitelet form after submit?

I have deveoped suitelet script to show textarea type field. I am populating sublist based on entered textarea field values. I am getting entered textarea field values from client script saverecord to suitelet and populate the suitelet sublist.Populating sublist in Get only.

Now, the challenge is, when I click on submit button, entered textarea values go away. User may enter value with new line/space/comma/pipe seperator. I want to show same values with same seperator in textarea field after clcickng on submit button.

Here is suitelet script sample, if (context.request.method === 'GET') { var form = serverWidget.createForm({ title: 'CON Numbers', hideNavBar: false });

                    form.clientScriptFileId = CLIENT_SCRIPT_FILE_ID;

                    var pageId = parseInt(context.request.parameters.page) || 0;
                    var scriptId = context.request.parameters.script;
                    var deploymentId = context.request.parameters.deploy;
                    var cidnParam = context.request.parameters.cidn;
                    var download = context.request.parameters.download; // Check       for download parameter

                    var sublist = form.addSublist({
                        id: 'custpage_table',
                        type: serverWidget.SublistType.LIST,
                        label: 'Sales Order Items'
                    });

                    sublist.addField({ id: 'id', label: 'Internal ID', type:     serverWidget.FieldType.TEXT });
               

                    var cidnField = form.addField({
                        id: 'custpage_enter_cidn',
                        label: 'Enter CON Numbers',
                        type: serverWidget.FieldType.TEXTAREA
                    });

               
                    form.addSubmitButton({
                        id: 'custpage_submit',
                        label: 'Submit'
                    });

                    context.response.writePage(form);
                }
       
        }

The value of custpage_enter_cidn will get submitted with the form, so you can grab its value from the parameters during a POST request just like you do with pageId, scriptId, etc.

Get the value of custpage_enter_cidn from the parameters, then set that as the defaultValue of cidnField.

See details on the defaultValue property.