ANYBODY MAN ENOUGH TO HELP?

Hi I have a text field with(multiline and wordwrap)...What I want is that when a user clicks a button the text should appear on the 1st line of the textfield ...when clicked again it should appear on the second line of the textfield.. and so on..

In short with every click.. the desired text should appear on a new line in the textfield


Thanx



Urgent pls help