textarea problem

[zuzupus]

hi,
i created a form having textbox field and besides that there is image when i click on this image a pop window open having text area and 2 buttons clear and add,so when i type soem message in text area and clcik on add it will add in this text field and clear to clear the message

now problem ,is it possible when i type in TEST in this textbox field and clicks on thsi image i can see this TEST in text area field and when change it saves in this textbox

also when i type let say 20 characters in text area and save in text field as this text field size is limited upto 12 he cant see rest 8 characters so when i mouseon this textbox field i can see the whole message upto 20 characters or some alert message

thanks in advance