how to create new class in javascript code example

Example 1: create element javascript with class

// create div element by javascript with class

var div = document.createElement('div');
div.className = "div1";

Example 2: class javascript

class Polygon {
  constructor(height, width) {
    this.height = height;
    this.width = width;
  }

  get area() {
    return this.calcArea();
  }

  calcArea() {
    return this.height * this.width;
  }
}

const square = new Polygon(10, 10);

console.log(square.area);