ASP dynamic form

I require a very small piece of ASP / java to be written, At present I have a simple text form field which is used as the subject ticket of a message. I want to change that to a drop menu option with a slight difference. When the drop menu is selected it must self submit itself and open a text box below based on the option chosen. ie. the option in the drop menu are 1,2,3,4and 5 the user selects option 2. Instantly below the drop menu, some text apears saying, you have selected option 2...blah blah. if the customer then changes the selected menu option then the text changes. The selected option must still be part of the form and carry a value but the displayed text below has nothing to do with the form. Probably really simple ....... ## Deliverables well commented code in asp or java ## Platform none