how to change or replace numbers entered by user in the textbox to asterisk (*) and how to show jquery.balloon popup on hover on textbox

how to change or replace numbers entered by user in the textbox to asterisk (*) and how to show jquery.balloon popup on hover on textbox

Here the scenario and the code

1)when the user enters number in the textbox it should be masked  as *
2)When the user hover the textbox then it should show the number which  user used entered as tooltip
3)when the user enters something in the textbox the tooltip should not be shown

see the code 


Please help.
Note : Dont ask me why to replace the numbers into * .That is the requirement