JavaScript通过prototype给对象定义属性用法实例

<script type="text/javascript">
<!--
function movieToString() {
  return("title: "+this.title+" director: "+this.director);
}
function movie(title, director) {
  this.title = title;
  this.director = director || "unknown"; //if null assign to "unknown"
  this.toString = movieToString; //assign function to this method pointer
}
var officeSpace = new movie("OfficeSpace");
var narnia = new movie("Narnia","Andrew Adamson");
movie.prototype.isComedy = false; //add a field to the movie's prototype
document.write(narnia.toString());
document.write("<br />Narnia a comedy"+narnia.isComedy);
officeSpace.isComedy = true; //override the default just for this object
document.write("<br />Office Space a comedy"+officeSpace.isComedy);
//-->
</script>