JavaScript通过function构造函数定义对象并绑定toString方法

<script type="text/javascript">
function movieToString() {
  return("title: "+this.title+" director: "+this.director);
}
function movie(title, director) {
  this.title = title;
  this.director = director;
  this.toString = movieToString; //assign function to this method pointer
}
  var aliens = new movie("Aliens","Cameron");
  document.write(aliens.toString());
</script>