Web Development: Unraveling HTML, CSS, and JavaScript/

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Functions are First Class Citizens

Functions are First Class Citizens

In this lesson, we'll study JavaScript functions and how they can be used in tandem with objects. Let's begin! :)

We'll cover the following...

Object instances in JavaScript can have properties that contain special objects, called functions.

After you assign a function to an object, you can use the corresponding property to invoke that function

This is shown in the Listing below:

Listing: Assigning functions to objects

<!DOCTYPE html>
<html>
<head>
  <title>Functions</title>
  <script>
    // Define a constructor for Car
    var Car = function (manuf, type, regno) {
      this.manufacturer = manuf;
      this.type = type;
      this.regno = regno;
      this.getHorsePower =
        function () { return 97; }
    }

    // Create a Car
    var car = new Car("Honda",
      "FR-V", "ABC-123");
    console.log("Horse power: " +
      car.getHorsePower());

    // It is a stronger car
    car.getHorsePower =
      function () { return 127; };
    console.log("Horse power: " +
      car.getHorsePower());
  </script>
</head>
<body>
  Listing 7-3: View the console output
</body>
</html>
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