The origin of the data in the javascript can be found in CodeBehind: (part III).

Look for the part:
Select Case strFieldType
Case "varchar"
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex))
Case "int"
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetInt32(intPrimaryRecordFieldIndex))
Case "decimal"
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetDecimal(intPrimaryRecordFieldIndex))
Case "datetime"
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetDateTime(intPrimaryRecordFieldIndex))
Case "boolean"
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetBoolean(intPrimaryRecordFieldIndex))
Case "money"
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetDecimal(intPrimaryRecordFieldIndex))
Case Else
strSQLFieldContent = " " & GetShortObjectName(dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex))
Select Case dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex)
Case dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex).ToLower.Contains("_mail")
'strSQLFieldContent = "<a href=mailto:" & dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex) & "></a>"
Case dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex).ToLower.Contains("_url")
'strSQLFieldContent = "<a href=http://" & dbDataReaderDDL.GetString(intPrimaryRecordFieldIndex) & "></a>"
End Select
End Select
lstFieldContentList_TrajectType.Add(strSQLFieldContent)
lstKeepListNewContent_TrajectType.Add("<input type = 'Text' id='" & lstFieldList_TrajectType(intPrimaryRecordFieldIndex) & "' name='" & lstShortFieldList_TrajectType(intPrimaryRecordFieldIndex) & "'/>")
lstKeepListInnerHTML_TrajectType.Add("input type = 'Text' id='" & lstFieldList_TrajectType(intPrimaryRecordFieldIndex) & "' name='" & lstShortFieldList_TrajectType(intPrimaryRecordFieldIndex) & "'")

'================ Start TraceLog ================
strItem = "Datareaders: PopUp_TrajectType"
strDetail = "strSQLFieldName: " & lstFieldList_TrajectType(intPrimaryRecordFieldIndex)
strResult = "strSQLFieldContent: " & strSQLFieldContent
TraceLog(strModule, strItem, strDetail, strResult)
'================= End TraceLog =================

intPrimaryRecordFieldIndex = intPrimaryRecordFieldIndex + 1
End While
End While
strInnerHTML_TrajectType = "<input type = 'Text' id='" & lstFieldList_TrajectType(intPrimaryRecordFieldIndex) & "' name='" & lstFieldList_TrajectType(intPrimaryRecordFieldIndex) & "'/>"
strPopUp_TrajectType_FieldContent = String.Join("<br>", lstFieldContentList_TrajectType.ToArray())
strPopUp_TrajectType_FieldNewContent = String.Join("<br>", lstKeepListNewContent_TrajectType.ToArray())