Arrays, objects and methods

<script type="text/javascript">

                var movies = [
                    {
                        title: "Red Sparrow",
                        hasWatched: true,
                        rating: 6.6
                    },
                    {
                        title: "Wonder",
                        hasWatched: true,
                        rating: 8
                    },
                    {
                        title: "Wedding Crashers",
                        hasWatched: false,
                        rating: 7.0
                    },
                    {
                        title: "The Internship",
                        hasWatched: true,
                        rating: 6.3
                    },
                    {
                        title: "Starsky & Hutch",
                        hasWatched: true,
                        rating: 6.1
                    },
                    {
                        title: "Meet the Fockers",
                        hasWatched: true,
                        rating: 6.3
                    }
                ]
                rater.prototype.percentage = function(movieRating, scale){
                        return (movieRating/scale) * 100;
                    }


                var movieTitle = "";
                var theRating = 0.0;


                for (counter = 0; counter < Object.keys(movies).length; counter++){
                    movieTitle = movies[counter].title;
                    theRating = (movies.percentage(movies[counter].rating,10));
                    document.write("<p>");
                    document.write("<b>Movie title: </b>" + movieTitle + "<br>");
                    document.write("<b>IMDB Rating: </b>" + theRating.toFixed(2) + "<br>");
                    document.write("</p>");
            }
            </script>