JSDoc adding real code in documentation

@example http://code.google.com/p/jsdoc-toolkit/wiki/TagExample

/**
 * This function does something see example below:
 * @example
 * var x = foo("test"); //it will show "test" message
 *
 * @param {string} str: string argument that will be shown in message
 */
function foo(str)
{
   alert(str);
}