Javascript: functions

function-definition.js

// Define a function within itself
var myfunction = function fun(number) {
  myfunction = function( number ) {
    return ++number;
  };
  return number * 2;
};

alert(myfunction(10)); // 20
alert(myfunction(10)); // 11


// Make a function to something expensive once, then cache for everyone else 
var myfunction = function fun(number) {
  // do object setup
  var local = {};
  myfunction = function() { return local;};
  return local;
};