javascript中实现继承的示例

来源：互联网发布：捕蜂器淘宝编辑：程序博客网时间：2024/05/17 23:41

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>对象继承的示例</title>
   <script type="text/javascript">
       //对象继承的示例
       //NaN 是 Not a Number的意思
       function Shape(edge) {
           this.edge = edge;
       }
       Shape.prototype.getArea = function() {
           return -1;
       }
       //三角形
       function Triangle(bottom, height) {
           Shape.call(this, 3);
           this.bottom = bottom;
           this.height = height;
       }

       Triangle.prototype = new Shape();

       Triangle.prototype.getArea = function() {
           return 0.5 * this.bottom * this.height;
       }

       Triangle.prototype.getEdge = function() {
           return this.edge;
       }

       var triangle = new Triangle(10, 4);

       alert(triangle.getEdge());
       alert(triangle.getArea());

       //四边形
       function Rectangle(bottom, height) {
           Shape.call(this, 4);
           this.bottom = bottom;
           this.height = height;
       }

       Rectangle.prototype = new Shape();

       Rectangle.prototype.getArea = function() {
           return this.bottom * this.height;
       }

       Rectangle.prototype.getEdge = function() {
           return this.edge;
       }
       var rectangle = new Rectangle(20, 40);
       alert(rectangle.getEdge());
       alert(rectangle.getArea());

   </script>
</head>
<body>

</body>
</html>

0 0