how to store value in a textarea column apex_item.checkbox tabular form store value as a delimiter

I want to display selected row value in a textarea from a tabular form and update table as per row value.

tabular form source query: SELECT apex_item.checkbox2(1, document_no) check$01,
document_no as DOCNO,
BRANCH_CD,trans_tp, document_dt as Trans_dt ,account_cd as Ac_cd,reverse_cd as Rev_cd,
naration,Debit_Amt,Credit_Amt,CHECKED_BY,CHECKED_DT,APPROVED_BY,APPROVED_DT,APPROVED
 from transection
where LTRIM(RTRIM(TRANSECTION.BRANCH_CD))=LTRIM(RTRIM(:P300_BRANCH_CD))
AND TRANSECTION.DOCUMENT_DT=:P300_TRANS_DT
AND LTRIM(RTRIM(TRANSECTION.TRANS_TP))=LTRIM(RTRIM(:P300_TRANS_TP))
AND LTRIM(RTRIM(NVL(TRANSECTION.APPROVED_BY,'I')))='I'

my js code is

var empNoS = $('.uReportStandard input[type=checkbox]:checked').map(

                       function() {

                                   return $(this).parent().parent().find('td[headers="DOCNO"] input').val();

                                  }

                     ).get().join(',');

$('#P300_TRANS_NO').val(empNoS);

not showing any value in textarea.

pls.help me.