Popup Message instead of lblMessage

I want show this "lblMessage.Text = "Message sent successfully.";" message in a popup upon Clicking on the submit button. How do i do that in as开发者_StackOverflow中文版p.net?

Change the text after hiding all the form. Choose an update panel where it will update asynchronously and after the completion of the event replace it with a label and set the text to message sent succesfully. Thats what i can understand from the description. If you can provide your scenario it would be more helpful. or if you want to show a popup message then this would be helpful