Functions :

• Will calling the function if we forget to place the parentheses, then we are getting the function definition only, but not the function output.
• A set of statements that performs a task or calculates a value.
• Defining a function does not execute it. Defining it names the function and specifies what to do when the function is called.
• Calling the function actually performs the specified actions with the indicated parameters.

Function statement :

• Declaring a function is called a function statement.
• It is also called a function declaration.

Example :

function sum(){
	console.log( " function statement");
}

Function Expression :

• Assigning a function to a variable.
• The function acts as a value.
• Function called through variable name only, otherwise gives an error

Example:

var add= function (num , num2){
	return num+ num2;
}
add(10,25);  // function called through variable name

Difference between statement and expression :

Hoisting applies to the function statement.

Hoisting is not applicable for a function expression.