How restrict TextArea that it only contain stirngs

Hi,
Hope you all are fine. Can any one tell me if i want that my TextArea contain only string then how can i do it. Means if user type only alphabets then letters types in text area but if user try to enter any thing other than alphabets then it shouldn't type in the textarea. I saw the constraint but i didn't see any constraint regarding string. There are NUMERIC, ANY but no one like STRING.

Thanks

Careful about what you are looking for here because you will most likely cripple your application. Which alphabets are you talking about? What does the text box represent?

Hi :),
Thanks. It contains only text message. Contains only alphabets A-Z or a-z. But no numeric value. It cantains fullstop(.), comma(,), etc but no numeric value.

Thanks.

Use a DocumentFilter.