20.1.5 Showing Messages Programmatically

Show and clear success or error messages from PL/SQL or JavaScript code.

Use APEX_ERROR.ADD_ERROR to signal an error in server-side code with a message the user sees in the notification area. In your page, you can react to events and call JavaScript APIs to show success messages. You can also use JavaScript to both show and clear error messages.

• Adding an Error Message in PL/SQL
  Use APEX_ERROR.ADD_ERROR to add an error message from server-side processing.
• Displaying Messages with JavaScript
  Show and clear page or field-level messages from JavaScript, including errors returned by eager server-side checks.