topical media & game development

topical media & game development

[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

professional-javascript-04-zInheritExample2.htm / htm


  <html>
  <head>
  <title>Example</title>
          <script type="text/javascript" src="zinherit.js"></script>
  </head>
  <body>
  <script type="text/javascript">
  function Polygon(iSides) {
      this.sides  = iSides;
      
      if (typeof Polygon._initialized == "undefined") {
  
          Polygon.prototype.getArea = function () {
              return 0;
          };    
          
          Polygon._initialized = true;
      }
  }
  
  function Triangle(iBase, iHeight) {
      Polygon.call(this, 3);
      this.base = iBase;
      this.height = iHeight;
      
      if (typeof Triangle._initialized == "undefined") {
          
          Triangle.prototype.inheritFrom(Polygon);
          Triangle.prototype.getArea = function () {
              return 0.5 * this.base * this.height;
          };    
          
          Triangle._initialized = true;
      }
  }
  
  function Rectangle(iLength, iWidth) {
      Polygon.call(this, 4);
      this.length = iLength;
      this.width = iWidth;
      
      if (typeof Rectangle._initialized == "undefined") {
      
          Rectangle.prototype.inheritFrom(Polygon);
          Rectangle.prototype.getArea = function () {
              return this.length * this.width;
          };    
          
          Rectangle._initialized = true;
      }
  }
  
  var triangle = new Triangle(12, 4);
  var rectangle = new Rectangle(22, 10);
  
  alert(triangle.sides);
  alert(triangle.getArea());
  
  alert(rectangle.sides);
  alert(rectangle.getArea());
  
  alert(triangle.instanceOf(Triangle));
  alert(triangle.instanceOf(Polygon));
  alert(rectangle.instanceOf(Rectangle));
  alert(rectangle.instanceOf(Polygon));
  
  </script>
   
  </body>
  </html>

[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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