   Authors need to be able to put code samples in their documents. If these samples are in JavaScript, they can be run by the users. Here's a very simple example, which squares and sums the numbers up to 10.

            ```javascript; runnable
            var result = 0;
            for (var i = 1; i <= 10; i++) {
                result += i * i;
            }
            return result;
            ```

            Code samples are written (and run) as functions, and the function's returned value is displa