can i use javascript class code example

Example 1: es6 class example

<script>
   class Student {
      constructor(rno,fname,lname){
         this.rno = rno
         this.fname = fname
         this.lname = lname
         console.log('inside constructor')
      }
      set rollno(newRollno){
         console.log("inside setter")
         this.rno = newRollno
      }
   }
   let s1 = new Student(101,'Sachin','Tendulkar')
   console.log(s1)
   //setter is called
   s1.rollno = 201
   console.log(s1)
</script>

Example 2: javascript class

// Improved formatting of Spotted Tailed Quoll's answer
class Person {
	constructor(name, age) {
		this.name = name;
		this.age = age;
	}
	introduction() {
		return `My name is ${name} and I am ${age} years old!`;
	}
}

let john = new Person("John Smith", 18);
console.log(john.introduction());

Example 3: es6 class example

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

Example 4: es6 class example

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