Define a Function

functions.js

// function constructor : the last paramater is the function logic, everything before it is a paramater
var theConstructor = new Function('x', 'y', 'return x + y');

// function statement
function theStatement(x, y) {
	return x + y
};

// function expression
var theExpression = function(x, y) {
	return x + y;
};

console.log(theConstructor(2,2), theStatement(2,2), theExpression(3,3));