Functions

Functions are code blocks that can have arguments, and function have their own scope. In JavaScript, functions are a very important feature of the program, and especially the fact that they can access local variables of a parent function (this is called a closure).

There are two ways to define functions in JavaScript - named functions and anonymous functions.

To define a named function, we use the function statement as follows:

function greet(name)
{
    return "Hello " + name + "!";
}

console.log(greet("Eric"));      // prints out Hello Eric!

In this function, the name argument to the greet function is used inside the function to construct a new string and return it using the return statement.

To define an anonymous function, we can alternatively use the following syntax:

var greet = function(name)
{
    return "Hello " + name + "!";
}

console.log(greet("Eric"));      // prints out Hello Eric!

Exercise

Define a function called multiplyFive which accepts a number and returns that number multiplied by 5.