To initialize and create an object in Javascript, a constructor method is used which is called when memory is allocated for an object. A class in Javascript can contain one constructor method only, however, a parent class constructor can be used by using the super keyword.
Example:
<!DOCTYPE html> <html> <body> <script> class Student { constructor() { this.firstname= "Mahesh"; this.lastname = "Kumawat"; } } var student = new Student(); document.writeln(student.firstname+" "+student.lastname); </script> </body> </html>
JavaScript calls parent class constructor example:
<!DOCTYPE html> <html> <body> <script> class CollegeName { constructor() { this.college="NC College"; } } class Student extends CollegeName{ constructor(rollNo,name) { super(); this.rollNo=rollNo; this.name=name; } } var stu= new Student(1,"Sue"); document.writeln(stu.rollNo+" "+stu.name+" "+stu.college); </script> </body> </html>