dynamic character selection

[dan000]

I have a product that requires 2 things:
input field : for entering a name for customizing clothing
selection tab : for choosing how many letters are in that field

the selection field (eg. 1-10 letters) is for charging the right price acording to how many letters are in the custom text field.

Now, I can't always trust that people will choose the right amount of letters they have typed in the text field.

my question is: Is there a way to use javascript to dynamically "select" the amount of letters entered in the text field?

http://bianca.affordablehost.com/~da...products_id=77