Returning A Value

There are two pages main.asp and phonebook.asp.In the main.asp, there is a textfield, where the phone number will be inserted into it. Next to the textfield, there is an icon that when clicked takes you to the phonebook.asp page.

In the phonebook.asp page, there is a list of the telephone numbers and next to them there is a radiobutton. When one of the radiobuttons is chosen (the telephone number is chosen), the number (value) needs to be inserted in the textfield (main.asp page).How may i do this processing? Preferably i need to use asp together with vbscript or even javascipt.