new运算符动态建立矩形对象r1

Sorry, as an AI language model, I am not able to execute code or create objects in real-time. However, here's an example of how you can dynamically create a rectangle object using the `new` operator in JavaScript:

// Define a Rectangle class
class Rectangle {
  constructor(width, height) {
    this.width = width;
    this.height = height;
  }
  
  get area() {
    return this.width * this.height;
  }
}

// Create a new rectangle object dynamically
const r1 = new Rectangle(10, 20);

console.log(r1.area); // Output: 200

In this example, we define a `Rectangle` class with a constructor that takes `width` and `height` as parameters. We also define a `get` accessor for the `area` property, which calculates the area of the rectangle.

Then, we use the `new` operator to create a new `Rectangle` object with the `width` of 10 and `height` of 20, and assign it to the variable `r1`. Finally, we log the area of `r1` to the console, which outputs `200`.