Creating an Object and Using Object Instance Properties and Methods : Objects Object Oriented « Language Basics « JavaScript DHTML






Creating an Object and Using Object Instance Properties and Methods

 
/*

Learn How to Program Using Any Web Browser
by Harold Davis 

Apress CopyRight 2004

ISBN: 1590591135
*/

<HTML>
<HEAD>
<TITLE>Instance method demo</TITLE>
</HEAD>
<BODY>
<H1>
<SCRIPT> 
   function Rectangle(height, width){ 
   // constructor function 
      this.height =  height; 
      this.width = width; 
   } 
   // create the function 
   function calc_Area () { 
      return this.height * this.width; 
   } 
   // turn the function into an object method 
   Rectangle.prototype.calcArea = calc_Area; 
   // instantiate the object 
   var theRectangle = new Rectangle (3, 5); 

   // set an instance property 
   theRectangle.width = 10; 

   // call and display the instance properties and method return 
   document.write("The rectangle instance height is: " + theRectangle.height + "<br>"); 
   document.write("The rectangle instance width is: " + theRectangle.width  + "<br>"); 
   document.write ("The calcArea method returns: " + theRectangle.calcArea()); 
   </SCRIPT>
</H1>
</BODY>
</HTML>

           
         
  








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