Defining Functions

There are at least three different ways to define a function in JavaScript. The first one is the traditional one:

function first(param) {
  alert(param + " method to define a function");
}

The second way to define a function is the anonymous way. You define a function inline, without giving it a name:

second = function(param)
  {alert(param + " method to define a function")};

function Employee() {
  var registerA = "Initial Value";
  this.setRegisterA = function(param) { registerA = param };
  this.dept = "HR";
  this.manager = "John Johnson";
}

Let's use it now. First, create a variable of class Employee:

var Ken = new Employee;

And then store a new value in registerA:

Ken.setRegisterA("new value stored in registerA");

The third way to define a function is by constructing it with the Function function. The Function function accepts two parameters: the parameter to be passed, and the body of the function:

third = new Function("param",
  "alert(param + ' method to define a function')");

Next: How to define a method