Javascript Function Declaration vs Expression

In this article, we will see what is the difference between javascript function declaration vs expression.

Function Declaration vs Expression

1. We can call a function before the function definition

wish(); // no error

function wish()
{
document.write("Hi");
}

2. We cannot create a variable for creating a function declaration
Syntax:

function functionname()
{
printing statement;
}

1. We cannot call a function before the function definition

wish(); //error: wish is not a function

var wish = function()
{
document.write("Hi");
}

Note: Function declarations are hoisted not function expressions.

2. We should create a variable for creating a function Expression
Syntax:

var variablename = function()
{
printing statement;
}