help with function

[someusernamehere]

Hey, I need some help, how I can write a simple lisp code which ask
for a value, after store in a variable, indeed I want to the value is
concatenate to an url, I have the following:

which found on google:

(defun search-word ()
 (interactive)
 (browse-url
  (concat "http://foo.bar.foobar/index.php?search=";
          (thing-at-point 'word))))

but this is only with the word at point, I want ask a word, any help?

thanks