Simple function examples showing function expressions vs. function declarations

func-decl-example.js

// simple example of a function declaration
function double (number) {
  var result = 2 * number;
  return result;
}

func-expr-example.js

// simple example of a function expression
var double = function (number) {
  var result = 2 * number;
  return result;
}; // don't forget to add a semicolon!