// Define a constructor method for our class. // Use it to initialize properties that will be different for // each individual Circle object. functionCircle(x, y, r) { this.x = x; // The X-coordinate of the center of the circle } // Create and discard an initial Circle object. // This forces the prototype object to be created in JavaScript 1.1. new Circle(0,0,0); // Define a constant: a property that will be shared by // all circle objects. Actually, we could just use Math.PI, // but we do it this way for the sake of instruction. Circle.prototype.pi = // Define a method to compute the circumference of the circle. // First declare a function, then assign it to a prototype property. // Note the use of the constant defined above. function Circle_circumference( ) { return Circle.prototype.circumference =Circle_circumference; // Define another method. This time we use a function literal to define // the function and assign it to a prototype property all in one step. Circle.prototype.area = // The Circle class is defined. // Now we can create an instance and invoke its methods. var c = var a =c.area( ); var p = c.circumference( ); // Returns true if the last character is c String.prototype.endsWith = return (c == } var message = message.endsWith('h') // Returns false message.endsWith('d') // Returns true
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